Thermostat the "culprit"
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Thermostat the "culprit"
I was wondering from my reasearch (well, kind of), is the thermostat the main "culprit" of our overheating problems.
I read that 195 is too high, however from what I am reading, almost everybody has lower thermo's and the car is overheating even worse. I noticed that people that have problems with overheating are mostly the ones with lower thermos. Now, why would that be a problem??? I know that I always ran 220 with a 195 thermo, I only once jumped over 220 on the highway, but never as far as my 180 thermo which ran 245 and the car's overflow just skyrocketed. I am starting to think that third gens. especially firebird owners need to think about this before spending a lot of money on the total cooling system.
Also there are a lot of posts on this subject and I know it, but none of them really answer the following questions that they are suposed to answer.
1. Does lowering your thermo, help the car run cooler?
2. Is no thermo a way to go?
3. What is the best thing to do to battle overheating?
4. Lastly, what does it take to keep the car at 180*?
I know that when moderators read this might get an urge to close it, but I warn you, all the subjects that I tried researching have many people say yes and many saying no.
I want a firm answer that backs everything up, since I took somebody's advice and put in an 180 thermo, but all I was getting was overheating. It works fine for 30min. drives, but it seems like it does not hold the heat at certain temp, so after the fan kicks in and cools the car down, the temp keeps rising and it does not stop. So i really need some concrete answers and not some BS that many people tend to write when it comes to cooling questions.
Thanks.
I dont like it.
I read that 195 is too high, however from what I am reading, almost everybody has lower thermo's and the car is overheating even worse. I noticed that people that have problems with overheating are mostly the ones with lower thermos. Now, why would that be a problem??? I know that I always ran 220 with a 195 thermo, I only once jumped over 220 on the highway, but never as far as my 180 thermo which ran 245 and the car's overflow just skyrocketed. I am starting to think that third gens. especially firebird owners need to think about this before spending a lot of money on the total cooling system.
Also there are a lot of posts on this subject and I know it, but none of them really answer the following questions that they are suposed to answer.
1. Does lowering your thermo, help the car run cooler?
2. Is no thermo a way to go?
3. What is the best thing to do to battle overheating?
4. Lastly, what does it take to keep the car at 180*?
I know that when moderators read this might get an urge to close it, but I warn you, all the subjects that I tried researching have many people say yes and many saying no.
I want a firm answer that backs everything up, since I took somebody's advice and put in an 180 thermo, but all I was getting was overheating. It works fine for 30min. drives, but it seems like it does not hold the heat at certain temp, so after the fan kicks in and cools the car down, the temp keeps rising and it does not stop. So i really need some concrete answers and not some BS that many people tend to write when it comes to cooling questions.
Thanks.
I dont like it. 
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From: Bloomingdale,IL
Car: 91 RS
Engine: 305 Tbi (L03)
Transmission: 700r4
1-In theory a lower thermostat should help the car run cooler. I beileve that one reason people with lower thermostats have cars that overheat is because they use it as a crutch. There is probably something wrong another part in the cooling system and they replace the cheapest part in an attempt to fix it.
One reason a car will begin to run hotter with a cooler thermostat is a faulty radiator. With a lower stat coolant will spend less time in the radiator. It may not spend enuf time there to disapte its heat.
2-Running no thermostat is not something you want to do. Coolant wont spent enuf time in the engine to pull heat from the motor. It also will fly through the radiator so you wont be disipating much of that heat to the surrounding air. Youll also never get into closed loop which means youll run rich and waste fuel.
3-Other than having a properly functioning cooling system, the best thing you can do is run water with an additive. Water is a much more efficient coolant than a 50/50 mix of coolant.
4-Getting the car to run at 180 is something that is much more difficult to do. In theory its simple just use a 180 thermostat in a properly functioning system. The problem is that very little air goes to the radiator in our cars. Anything you can do to get more air in there will help.
One reason a car will begin to run hotter with a cooler thermostat is a faulty radiator. With a lower stat coolant will spend less time in the radiator. It may not spend enuf time there to disapte its heat.
2-Running no thermostat is not something you want to do. Coolant wont spent enuf time in the engine to pull heat from the motor. It also will fly through the radiator so you wont be disipating much of that heat to the surrounding air. Youll also never get into closed loop which means youll run rich and waste fuel.
3-Other than having a properly functioning cooling system, the best thing you can do is run water with an additive. Water is a much more efficient coolant than a 50/50 mix of coolant.
4-Getting the car to run at 180 is something that is much more difficult to do. In theory its simple just use a 180 thermostat in a properly functioning system. The problem is that very little air goes to the radiator in our cars. Anything you can do to get more air in there will help.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Wow, first post and we nailed it. Awsome.
I aggree with everything you say, but I have a new radiator and I am replacing the hoses with stainless stele and the water pump as well. Everything else is new. I will replace the thermo with a delco thermo but still 180.
Also, is the three row radiator enough for cooling the 305?
Is one fan enough ? ( NO!, but open to opinions).
I will be getting level 1 chip from TBI chips.com and it makes the car run at 160-180 which is perfect, advanced timing and all the good stuff.
In the end I will be down bout 250bucks, but my car will finally get the treatement it deservs.
Keep the questions coming, and please if you are here to cause BS than please leave.
Thanks
I aggree with everything you say, but I have a new radiator and I am replacing the hoses with stainless stele and the water pump as well. Everything else is new. I will replace the thermo with a delco thermo but still 180.
Also, is the three row radiator enough for cooling the 305?
Is one fan enough ? ( NO!, but open to opinions).
I will be getting level 1 chip from TBI chips.com and it makes the car run at 160-180 which is perfect, advanced timing and all the good stuff.
In the end I will be down bout 250bucks, but my car will finally get the treatement it deservs.
Keep the questions coming, and please if you are here to cause BS than please leave.
Thanks
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From: Woodland Hills, CA USA
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Originally posted by dankhound
2-Running no thermostat is not something you want to do. Coolant wont spent enuf time in the engine to pull heat from the motor. It also will fly through the radiator so you wont be disipating much of that heat to the surrounding air. Youll also never get into closed loop which means youll run rich and waste fuel.
2-Running no thermostat is not something you want to do. Coolant wont spent enuf time in the engine to pull heat from the motor. It also will fly through the radiator so you wont be disipating much of that heat to the surrounding air. Youll also never get into closed loop which means youll run rich and waste fuel.
If you check the FAQ section you will find info. regarding Open and Closed Loop and info. straight from the GM manual as to what determines Closed Loop. The idea that too low of a thermostat preventing Closed Loop is a common misconception.
Q: What is the difference between 'Open Loop' and 'Closed Loop'?
A: When the engine is first started, and rpm is above 400 rpm, the system goes into 'Open Loop' operation. In 'Open Loop', the ECM will ignore the signal from the Oxygen (O2) sensor and calculate the air/fuel ratio based on inputs from the coolant and MAF sensors, but mostly from a pre-programmed table in the memcal.
The system will stay in 'Open Loop' until the following conditions are met:
1. The O2 sensor has varying voltage output, showing that it is hot enough to operate properly. (This depends on temperature)
2. The coolant sensor is above a specified temperature about 40°C/104°F.
3. A specific amount of time has elapsed after starting the engine.
The specific values for the above conditions vary with different engines and are stored in the mem-cal. When these conditions are met, the system goes into 'Closed Loop' operation. In 'Closed Loop', the ECM will calculate the air/fuel ratio (injector on-time) based on the various sensors but mainly the O2 sensor. This allows the air/fuel ratio to stay very close to 14.7:1.
A: When the engine is first started, and rpm is above 400 rpm, the system goes into 'Open Loop' operation. In 'Open Loop', the ECM will ignore the signal from the Oxygen (O2) sensor and calculate the air/fuel ratio based on inputs from the coolant and MAF sensors, but mostly from a pre-programmed table in the memcal.
The system will stay in 'Open Loop' until the following conditions are met:
1. The O2 sensor has varying voltage output, showing that it is hot enough to operate properly. (This depends on temperature)
2. The coolant sensor is above a specified temperature about 40°C/104°F.
3. A specific amount of time has elapsed after starting the engine.
The specific values for the above conditions vary with different engines and are stored in the mem-cal. When these conditions are met, the system goes into 'Closed Loop' operation. In 'Closed Loop', the ECM will calculate the air/fuel ratio (injector on-time) based on the various sensors but mainly the O2 sensor. This allows the air/fuel ratio to stay very close to 14.7:1.
Too low of a thermostat or no thermostast at all can cause the engine to take longer to warm up and also reduce the output of the heater, but believe me, the car will still eventually achieve an average temp based on coolant flow and driving conditions. No thermostat in a street car isn't a good idea since you want to maintain certain minimum temp to keep the sensors and ECM happy and keep the car running in the optimum air/fuel range.
Lastly, the concept that keeping the water in the radiator longer, keeps the engine cooler is also false. Look at it this way, if you're keeping the water in the radiator longer, then you're also keeping the water in the block longer – which means you're putting more heat into the water in the block.
From the Stewart Components Web site:
Thermostats & Restrictors
We strongly recommend NEVER using a restrictor: they decrease coolant flow and ultimately inhibit cooling.
For applications requiring a thermostat to keep the engine at operating temperature, we recommend using a Stewart/Robertshaw high flow thermostat. This thermostat does not restrict flow when open. The Stewart/Robertshaw thermostat enhances the performance of the cooling system, using any style of water pump. However, the Stewart Stage 1 high-flow water pump may require this thermostat to operate properly, and Stewart Stage 2, 3, and 4 water pumps simply will NOT operate with a regular thermostat because these pumps have no internal bypasses.
Stewart further modifies its thermostat by machining three 3/16" bypass holes directly in the poppet valve, which allows some coolant to bypass the thermostat even when closed. This modification does result in the engine taking slightly longer to reach operating temperature in cold weather, but it allows the thermostat to function properly when using a high flow water pump at high engine RPM.
A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures.
Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would overcome the radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool. Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it.
We strongly recommend NEVER using a restrictor: they decrease coolant flow and ultimately inhibit cooling.
For applications requiring a thermostat to keep the engine at operating temperature, we recommend using a Stewart/Robertshaw high flow thermostat. This thermostat does not restrict flow when open. The Stewart/Robertshaw thermostat enhances the performance of the cooling system, using any style of water pump. However, the Stewart Stage 1 high-flow water pump may require this thermostat to operate properly, and Stewart Stage 2, 3, and 4 water pumps simply will NOT operate with a regular thermostat because these pumps have no internal bypasses.
Stewart further modifies its thermostat by machining three 3/16" bypass holes directly in the poppet valve, which allows some coolant to bypass the thermostat even when closed. This modification does result in the engine taking slightly longer to reach operating temperature in cold weather, but it allows the thermostat to function properly when using a high flow water pump at high engine RPM.
A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures.
Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would overcome the radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool. Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it.
Last edited by BretD 88GTA; Aug 25, 2004 at 03:56 PM.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Yo, GTA I have read those things and I do not believe the crap about coolant staying in the engine long. Its a simple explanation, and it throws people off, just cuz its soo simple. Why in the blue hell would they sell "high flow" pumps if the coolant needed time to stay in the radiator???
Anyway, my problem comes from driving the car and it overheating. When I am sitting in traffic it actually cools down. Its strange but maybe my belt is not operating the way it should.
Do you think that a high flow pump would help my cause??
Anyway, my problem comes from driving the car and it overheating. When I am sitting in traffic it actually cools down. Its strange but maybe my belt is not operating the way it should.
Do you think that a high flow pump would help my cause??
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From: Woodland Hills, CA USA
Car: Yes...
Engine: Last time I checked...
Transmission: See "Engine"...
Originally posted by xlwhellraiser
Yo, GTA I have read those things and I do not believe the crap about coolant staying in the engine long. Its a simple explanation, and it throws people off, just cuz its soo simple. Why in the blue hell would they sell "high flow" pumps if the coolant needed time to stay in the radiator???
Anyway, my problem comes from driving the car and it overheating. When I am sitting in traffic it actually cools down. Its strange but maybe my belt is not operating the way it should.
Do you think that a high flow pump would help my cause??
Yo, GTA I have read those things and I do not believe the crap about coolant staying in the engine long. Its a simple explanation, and it throws people off, just cuz its soo simple. Why in the blue hell would they sell "high flow" pumps if the coolant needed time to stay in the radiator???
Anyway, my problem comes from driving the car and it overheating. When I am sitting in traffic it actually cools down. Its strange but maybe my belt is not operating the way it should.
Do you think that a high flow pump would help my cause??
I couldn't find anything wrong with the cooling system. What appears to have been the problem was the fuel system.
Fuel began leaking from the FPR into the plenum thru the vacuum line. After replacing the FPR diaphragm I then had 70psi of fuel pressure.
Turns out the return line from the FPR had become clogged and caused the high fuel psi. This eventually killed the FPR diaphragm.
Running with that much fuel psi must have been loading the engine up, making it run rich. This can cause higher engine temps and seems to explain why my car ran hotter under load.
After clearing the fuel return line and getting the fuel psi back to normal, the car now runs cooler.
You might try checking your fuel psi and also for a rich or lean condition. Another possibilty is a blown head gasket. You can have a blown gasket and not have any of the usual tell-tale signs such as coolant in the oil or vice-versa.
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From: Woodland Hills, CA USA
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Originally posted by xlwhellraiser
How do I go about cleaning my fuel line
How do I go about cleaning my fuel line
I removed the plenum, FPR cover and diaphragm, then disconnected the flexible return line next to the power steering pump.
Using my air compressor, I tried blowing air back thru the line and out the port on the base of the FPR. I couldn't get any air thru the line. The pressure simply held. Next, I tried blowing air from the FPR port out the return line. Again, no air would go thru the line.
At this point I pulled the fuel rail, took it apart and found the problem. Some way, some how, crud had built up in the return port on the FPR base and also about 1/4" of the soild return line. It was packed solid.
Using a small screw driver and throttle body cleaner, I cleaned out the return line. The FPR base showed some signs of corrosion, so I just bought a whole new assembly.
On your car, I'd start by simply checking the fuel psi. This can give you an indication if there is a problem in the fuel system.
On a TPI, with the engine idling and the vacuum line to the FPR disconnected, you should have around 45psi of fuel pressure. If it's around 60 to 70 psi (this is full pressure from the fuel pump a.k.a. "deadhead" pressure), then you could have a blockage in the return line.
If you have an adjustable FPR, make sure it is set correctly. Again, around 45 to 47psi at idle w/o vacuum is what you want.
I'd also inspect the radiator and check for corrosion, blocked tubes ...etc. Reduced flow thru the radiator can cause higher temps while driving. Something else to check is the radiator hoses. A weak lower hose can collapse under load and starve the water pump.
Last, what shape is the air dam under the car in? If the air dam is badly damaged or missing, you'll have poor air circulation at speed and again, could get higher temps while driving.
Last edited by BretD 88GTA; Aug 26, 2004 at 11:53 AM.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
I read your post on the stewart website, and it kind of sounds like the same problem I am having. So, I just bought a new air filter and some heavy duty fuel line cleaner. Also tomorow I get paid so i will replace the water hoses. The radiator I have is brand new, as well as thermo (which I will change as well), new overflow, and the water pump is working fine.
How do I check the fuel preassure?
I will check my lines as well.
Do you still have overheating problems???
How do I check the fuel preassure?
I will check my lines as well.
Do you still have overheating problems???
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From: Woodland Hills, CA USA
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Originally posted by xlwhellraiser
How do I check the fuel preassure?
I will check my lines as well.
Do you still have overheating problems???
How do I check the fuel preassure?
I will check my lines as well.
Do you still have overheating problems???
Once you have it hooked up, disconnect the FPR vacuum line from the plenum and be sure to cap the nipple. Start the engine and observe the gauge reading.
No overheating since repairing the fuel line and the car has been running cooler. My daily commute includes a hill climb thru a canyon and with the fuel line problem the temp was hitting close to 240° at times. Since repair, the temp only climbs to 220° going up the hill and cools down quickly on the downhill side.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
I went ahead and replaced the fuel filter (hasnt been replaced in a very long time. I also added a product to my fuel that's like the best cleaner (or so I've been told). I am very carefull when it comes to fuel lines, since (although taking the cap off) when I installed the new fuel filter, the fuel just ran all over the place and all over me. It was a panick attack since no matter what I put on it to jam it it just ran. But everything went OK and the new filter is in place.
I will have to take the car to the mechanic and have them check the lines.
I am also thinking of putting a sucker fan, or a fan switch.
I have a single fan set up, and I am getting a stage 1 chip from TBI chips (runs at either 160 or 180* and it has some timing adjustments).
Do you think a sinlge fan is enough, and if turned on earlier would it hold the temp. easier?
Also, what do you think about the thermo switch that mounts a probe in your radiator and than you can mannualy switch the *** to whichever temperature you want it to turn on?
I will have to take the car to the mechanic and have them check the lines.
I am also thinking of putting a sucker fan, or a fan switch.
I have a single fan set up, and I am getting a stage 1 chip from TBI chips (runs at either 160 or 180* and it has some timing adjustments).
Do you think a sinlge fan is enough, and if turned on earlier would it hold the temp. easier?
Also, what do you think about the thermo switch that mounts a probe in your radiator and than you can mannualy switch the *** to whichever temperature you want it to turn on?
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From: Woodland Hills, CA USA
Car: Yes...
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Transmission: See "Engine"...
Originally posted by xlwhellraiser
I went ahead and replaced the fuel filter (hasnt been replaced in a very long time. I also added a product to my fuel that's like the best cleaner (or so I've been told). I am very carefull when it comes to fuel lines, since (although taking the cap off) when I installed the new fuel filter, the fuel just ran all over the place and all over me. It was a panick attack since no matter what I put on it to jam it it just ran. But everything went OK and the new filter is in place.
I will have to take the car to the mechanic and have them check the lines.
I am also thinking of putting a sucker fan, or a fan switch.
I have a single fan set up, and I am getting a stage 1 chip from TBI chips (runs at either 160 or 180* and it has some timing adjustments).
Do you think a sinlge fan is enough, and if turned on earlier would it hold the temp. easier?
Also, what do you think about the thermo switch that mounts a probe in your radiator and than you can mannualy switch the *** to whichever temperature you want it to turn on?
I went ahead and replaced the fuel filter (hasnt been replaced in a very long time. I also added a product to my fuel that's like the best cleaner (or so I've been told). I am very carefull when it comes to fuel lines, since (although taking the cap off) when I installed the new fuel filter, the fuel just ran all over the place and all over me. It was a panick attack since no matter what I put on it to jam it it just ran. But everything went OK and the new filter is in place.
I will have to take the car to the mechanic and have them check the lines.
I am also thinking of putting a sucker fan, or a fan switch.
I have a single fan set up, and I am getting a stage 1 chip from TBI chips (runs at either 160 or 180* and it has some timing adjustments).
Do you think a sinlge fan is enough, and if turned on earlier would it hold the temp. easier?
Also, what do you think about the thermo switch that mounts a probe in your radiator and than you can mannualy switch the *** to whichever temperature you want it to turn on?
Going from a single fan to dual fan set-up isn't a bad idea, but I'm not sure that you need to go that extreme just yet.
It sounds like your engine is pretty much stock, so I 'd just check everything out in the cooling system to make sure it's all in good shape. After that, you can try a lower thermostat, second fan ...etc.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
GTA I just want to say thanks, for trying to help me out.
I knew what you were talking about when you were reffering to the fuel lines. A friend of mine has TBI as well and the fuel lines were a problem. He told me that he switched to the hoses instead of the metal lines and the car did run cooler, it was just a poor design. However, I have a vented cap (which I just noticed, and bought it with the radiator). I think that it might be the problem since, i guess, will let the air enter, and the preassure will lack a bit. I might be wrong.
I read on the thirdgen tech articles that the temp. for the fan to turn on is way too late, so even if it cools down the temp of the motor will make it rise again. So, I thought of getting that thermostatick switch, and have the fan turn on earlier on hot days, and have it almost stock on cold days.
I will change my hoses, I'll get them in stainless steel too, and other than watterpump being stock everything else on that car's cooling system will be new.
Do you have any suggestions to what kind of fan, might work better, if any??
Or would a water pump help ( I read your posts on stewart and it only seems to open up new problems).
Once again thanks for your help.
I knew what you were talking about when you were reffering to the fuel lines. A friend of mine has TBI as well and the fuel lines were a problem. He told me that he switched to the hoses instead of the metal lines and the car did run cooler, it was just a poor design. However, I have a vented cap (which I just noticed, and bought it with the radiator). I think that it might be the problem since, i guess, will let the air enter, and the preassure will lack a bit. I might be wrong.
I read on the thirdgen tech articles that the temp. for the fan to turn on is way too late, so even if it cools down the temp of the motor will make it rise again. So, I thought of getting that thermostatick switch, and have the fan turn on earlier on hot days, and have it almost stock on cold days.
I will change my hoses, I'll get them in stainless steel too, and other than watterpump being stock everything else on that car's cooling system will be new.
Do you have any suggestions to what kind of fan, might work better, if any??
Or would a water pump help ( I read your posts on stewart and it only seems to open up new problems).
Once again thanks for your help.
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From: Woodland Hills, CA USA
Car: Yes...
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Originally posted by xlwhellraiser
Do you have any suggestions to what kind of fan, might work better, if any??
Or would a water pump help ( I read your posts on stewart and it only seems to open up new problems).
Once again thanks for your help.
Do you have any suggestions to what kind of fan, might work better, if any??
Or would a water pump help ( I read your posts on stewart and it only seems to open up new problems).
Once again thanks for your help.
The Stewart water pump is good. I'm happy with my Stage II aluminum.
It was after installing it that I discovered my overheating issue, but I don't think the pump had anything to do with it. It just turned out that at the same time my fuel line problem revealed itself.
Good luck with your car and hopefully you will get it running a bit cooler.
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From: florida
Car: 1984 Pontiac Firebird
Engine: modded 5.0
Transmission: modded 700r4
t-stat
I replaced my 195* stat with a 180* unit and before it would run around 210-220, and when idling with the a/c on the temp would slowly climb. Now, with the 180, it runs between 180-190 and barely creeps at idle with the a/c on. So in my case, a cooler thermostat did help out quite a bit. No other cooling system components were changed and I dropped a consistent 30 degrees.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Hi, I just installed a Bosch high flow, heavy duty pump, and its a monster. It keept the car cool at 160-180. I replaced the radiator, new thermostat, new water pump, crappy air dam, but I am getting a new three piece one in a week. SO, this bird will run cool, its just the way it is.
Due to my dam not being as functional as it should, my temp will heat up while driving, however with the new pump its barely even noticeable. When the new dam arrives I will be rid of the cooling curse.
Thanks for all your help.
Due to my dam not being as functional as it should, my temp will heat up while driving, however with the new pump its barely even noticeable. When the new dam arrives I will be rid of the cooling curse.
Thanks for all your help.
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Joined: Feb 2001
Posts: 62
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From: New Zealand
Car: 86 TransAm
Engine: 360 SBC 4Bolt / Bowtie Heads
Transmission: T5 NWC Manual
Axle/Gears: Torsen T2 / 3.23
Hi... Just a few words on the Air dam and air circulation.
When I recently changed my motor for a 350 we did an initial run, after Cam break in, on a farely cool night with the bonnett and Air dam removed... I had a 170Deg thermostat in at the time and it ran around 220Deg! We removed the thermostat completely and still 220 plus on a cold night.
As soon as I put the Bonnett and Air dam back on... Wow! Now she ran far to cold. I'm now running a 180Deg thermostat and my car runs between 180 and 190 with no problems (Also have a fan switch around the 190Deg area).
I agree that the thermostat seems to determine the MINIMUM side more than anything else and that your Air dam, radiator, and to some degree fan, is what you should be checking. Just a thought... Geoff.
When I recently changed my motor for a 350 we did an initial run, after Cam break in, on a farely cool night with the bonnett and Air dam removed... I had a 170Deg thermostat in at the time and it ran around 220Deg! We removed the thermostat completely and still 220 plus on a cold night.
As soon as I put the Bonnett and Air dam back on... Wow! Now she ran far to cold. I'm now running a 180Deg thermostat and my car runs between 180 and 190 with no problems (Also have a fan switch around the 190Deg area).
I agree that the thermostat seems to determine the MINIMUM side more than anything else and that your Air dam, radiator, and to some degree fan, is what you should be checking. Just a thought... Geoff.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Ya, I agree the air damn (pun inteded) really does wonders. However, my air dam is only held with two screw and it pretty beat up. I just orderd a new set (3 pieces) and I am hoping that it works out. When I changed my pump the temp would run a lot cooler too, but without the air damn it will get up to about 220 and even more if its really hot. Yesterday i ran 170-180 for about half an hour in stop and go traffic, also it was around 93 degrees in denver. So, I was amazed to what a new water pump would do. However it got up to 222 when I started driving a bit. So a new air dam is the answer, cuz everything else in my cooling system is new. Also, my guage shows about 225 when my 180* thermostat kicks in. My fan is a myster too. I have a new sensor for it, but it seems like it wants to run a lot more than needed ( I am not sure if this is good or not). For example if I ran the car for about 20-30min. If I were to start it, the fan would come on too. However when it sits to where it completly cools down, the fan would come on later. I also have the switch to turn the fan on and off. However, it only turns on and the switch will not turn it off. Its odd, but would this be a problem for the car if the fan is behaving like this.
Also, would it be better to add another fan to the set up, and have them turn on at the same time?? Or even a mechanical fan??
I appreciate any input.
Also, would it be better to add another fan to the set up, and have them turn on at the same time?? Or even a mechanical fan??
I appreciate any input.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Whats air bonnet???? Is there something else to the air dam?? Please tell me no!!
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Joined: Feb 2001
Posts: 62
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From: New Zealand
Car: 86 TransAm
Engine: 360 SBC 4Bolt / Bowtie Heads
Transmission: T5 NWC Manual
Axle/Gears: Torsen T2 / 3.23
Sorry... Never been much of a speller. You know, the big steel thing that covers the engine bay.... I think you guys call it a Hood? Terminology difference... We call it a Bonnett down these parts (New Zealand). Apologies for the confusion.... Kind regards... Geoff.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Ok. It has nothing to do with stuff under the car, but it just covers the engine??
Its cool and kind of funny (if you dont mind me saying) I think I will call the hood bonnet now, just cuz it will make me sound more educated. Just kidding. I am glad that thats what you ment.
I am replacing the hoses tomorow, I am not sure if I can get that spring out of the lower one and put it into my new one?? Also, my thermo starts at 225 (according to my guage) its a 180 thermo, how is that possible. Mind that I have a new sensor that was installed after the head re-build.
Does this mean that my coolant is at 180, but the heads and intake at 225?? Please respond.
Thanks.
G0d bless.
Its cool and kind of funny (if you dont mind me saying) I think I will call the hood bonnet now, just cuz it will make me sound more educated. Just kidding. I am glad that thats what you ment.
I am replacing the hoses tomorow, I am not sure if I can get that spring out of the lower one and put it into my new one?? Also, my thermo starts at 225 (according to my guage) its a 180 thermo, how is that possible. Mind that I have a new sensor that was installed after the head re-build.
Does this mean that my coolant is at 180, but the heads and intake at 225?? Please respond.
Thanks.
G0d bless.
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Joined: Feb 2001
Posts: 62
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From: New Zealand
Car: 86 TransAm
Engine: 360 SBC 4Bolt / Bowtie Heads
Transmission: T5 NWC Manual
Axle/Gears: Torsen T2 / 3.23
Hmmm... I guess you could be getting the wrong info' from your gauge. I checked mine by finding someone with one of those laser temperature guns. Shine it on the base of the sensor and cross check with what your gauge says. Dont know about the fuel lines, mine's a carby job. Assuming you have good flow and a good radiator, pump and fan, you should be able to idle as long as you want with the fan kicking in every now and then to cool things back to normal. It's definately worth checking your gauge accuracy just in case you have a faulty gauge or incorrect sender. When you find the problem please post it for interest sake... Kind regards... Geoff.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
What do you guys think of installing an after market guage into the overflow???? It should tell us the temp. of the coolant. Isnt that what we need?? I might be wrong, but putting the sensor really close to the exaust manifold is insidious. The guage will never tell the right temperature. In my TBI there is a slim chance of installing a sensor in the intake next to the thermo, there is no space (I could be wrong, but from what am seeing, no no).
I am getting the air damn pretty soon, so I will post if that changed my cooling. Other than that everything in my cooling system is new and I will be pissed if it doesnt work.
Also, my lower hose (i havent chaged it yet cuz of coolant and stuff) is pretty hard. I checked it for cracks and what not, plus it has the metal spring in it. I was just wondering of how hard should that hose be. Its not to hard, but pretty sturdy.
Thanks.
P.S. One of my friends who's and oldschool mechanic has that laser guage so I will try to get to him this weekend. I am also working on my pro/am website for the interested, and working on my killswitch, new guages and cooling. Phew...
I am getting the air damn pretty soon, so I will post if that changed my cooling. Other than that everything in my cooling system is new and I will be pissed if it doesnt work.
Also, my lower hose (i havent chaged it yet cuz of coolant and stuff) is pretty hard. I checked it for cracks and what not, plus it has the metal spring in it. I was just wondering of how hard should that hose be. Its not to hard, but pretty sturdy.
Thanks.
P.S. One of my friends who's and oldschool mechanic has that laser guage so I will try to get to him this weekend. I am also working on my pro/am website for the interested, and working on my killswitch, new guages and cooling. Phew...
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From: Woodland Hills, CA USA
Car: Yes...
Engine: Last time I checked...
Transmission: See "Engine"...
Originally posted by xlwhellraiser
What do you guys think of installing an after market guage into the overflow????
What do you guys think of installing an after market guage into the overflow????
You could even install it into one of the radiator hoses I suppose by cutting the hose and inserting a piece of stainless steel tubing that has been drilled and tapped for a temp probe.
I recently bought a new aluminum direct-fit race radiator that already has a provision for a temp probe. I plan to install an AutoMeter water temp gauge under the hood with the new radiator.
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Joined: Jan 2002
Posts: 1,322
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From: Bloomingdale,IL
Car: 91 RS
Engine: 305 Tbi (L03)
Transmission: 700r4
Putting a temp gauge in the overflow is not what you want. You want to know the temp of the engine so the sensor must be put into the engine.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Ok, the overflow was just an idea. Where would you guys install a sensor (other than the driver side head) on a TBI stock motor??? ITs a myster to me.
Also, how hard should the bottom rad. hose be?? Is it good if its hard??
Also, how hard should the bottom rad. hose be?? Is it good if its hard??
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Joined: Jul 1999
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From: Katy, TX
Car: 1985 IROC Z-28
Engine: 355
Transmission: TH-350
Axle/Gears: 3:73
I'm running an all-aluminum rad. Everything else is stock, and the motor NEVER gets over 190 with a 180 stat. An all-aluminum rad is the ticket. At least 2 1" cores.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
It should be around 130-140 bucks. Its pretty cheap. You can probably get it from pep boyz or autozone and they are the same price as many cheap internet sites. The aluminum ones are a direct fit 3 row radiators. At least that is what I have.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Hey, does anyone know how to T- a driver side temp. sensor in order to install another water temp. guage?? Does T mean that I just cut the installation out and wrap the other guages wire on it, and insulate it again?? Is it like the same thing as in T-ing to the green and white wire on the fan relay to install the switch???
I appreciate the help.
Oh, yeah. How hard should the bottom rad. hose be and is it OK to have it on there without the spring. Also, can i take out the spring and put it on my new hose (direct replacement)??
Thanks again for your help.
Truly all the good people on this board make my car work and look better and I am grateful for that.
I appreciate the help.
Oh, yeah. How hard should the bottom rad. hose be and is it OK to have it on there without the spring. Also, can i take out the spring and put it on my new hose (direct replacement)??
Thanks again for your help.
Truly all the good people on this board make my car work and look better and I am grateful for that.
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From: East Tennessee
Car: 1992 Z28 Heritage Edition
Engine: L98
Transmission: T56
Axle/Gears: 3.23:1
Originally posted by dankhound
3-Other than having a properly functioning cooling system, the best thing you can do is run water with an additive. Water is a much more efficient coolant than a 50/50 mix of coolant.
3-Other than having a properly functioning cooling system, the best thing you can do is run water with an additive. Water is a much more efficient coolant than a 50/50 mix of coolant.
Just an FYI.
Edit, I just caught what you said about water plus an additive... In any case, my above statement is still true.
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thermostat
O.K. First of all i'm an auto student in college and the thermostat is there to keep a minimum freezing point AND maximum boiling point. Overheating is usually not caused by a thermostat, also "NO THERMOSTAT" is a very bad thing to do. It will be good for a while but will then start causing you some problems. One of the disadvantages of this is your car will take twice as longer to warm up beacuse the thermostat lets cold coolant go through only at a certain temp after the engine is warm. If cold coolant is constantly running through your engine will not warm up properly and cause damage to your engine and lag on you.
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Joined: Oct 2003
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From: Delta, PA
Car: 89 Firebird
Engine: L05 350 TBI
Transmission: 700r4-slippin' on it's last leg
Originally posted by Dante93GTZ
I'm not sure I agree with that. Simple physics states that adding something into water will lower the freezing temp and raise the boiling point. That's primarily why we use the coolant mix with water. Theoretically, if we just used straight water, it would boil over at 212*, a temperature which most of our motors see in daily traffic - Heck, our fans aren't even programmed to kick on until 220 or so!
Just an FYI.
Edit, I just caught what you said about water plus an additive... In any case, my above statement is still true.
I'm not sure I agree with that. Simple physics states that adding something into water will lower the freezing temp and raise the boiling point. That's primarily why we use the coolant mix with water. Theoretically, if we just used straight water, it would boil over at 212*, a temperature which most of our motors see in daily traffic - Heck, our fans aren't even programmed to kick on until 220 or so!
Just an FYI.
Edit, I just caught what you said about water plus an additive... In any case, my above statement is still true.
Alot of people never even think of the radiator cap as to a cause of overheating, but if it is not holding pressure, then the boiling point reverts to a lower temp.
After the 180º thermo install, the best way I found to keep the engine cool (180º constant), is to install a cooler temp fan switch and/or ground the coolant fan relay wire (green?), so that fan comes on when ignition is energized.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Hey, This post is still kicking, awsome. i would encourage some arguing but, no fighting please (.
Anyway, I totally replaced my whole cooling system.
New Radiator, new water pump, new hoses, new fan motor etc.
I found out what the problem was.
Thermostat (aint that the name of the post??)
Anyways, I bought a 180 thermo from pepboys and it was about 4 bucks. I put it in and the temp would get to about 230 and than it would come down. I thought that it was the problem with my fan so I installed a switch and I switched it on, but it did not affect anything. The temperature would still be 230 before it goes down to 170. Than I would drive to 200 and than well over 220. I was perplexed, and than one day I decided to go to NAPA and get a good thermostat. First I asked for the 170 stat, but they did not have it. Than I settled for 180 Superstat. I installed it and waited with engine idling. I looked at the temp and it got up to about 180 and than I touched the top hose and it started circulating coolant. Than I checked my guage and it was 180. My previous stat would not open untill 230 although it was a 180 stat. I was pissed. If I knew this I would have saved some money. Now my car drives between 170-190 all the time no matter the heat. My fan is almost none existant, although I still turn it on when the temp hits about 170. It does help, but not nearly as much as the stat.
So, when I first wrote this thread I knew there was something to do with a thermostat, but was not sure. Now, I am totally sure that for some of you outthere who have the problem of the car heating up over 220 and than going down, this might be the problem. Get yourself a very good thermostat, dont skipon it. As I found out its very important.
. Anyway, I totally replaced my whole cooling system.
New Radiator, new water pump, new hoses, new fan motor etc.
I found out what the problem was.
Thermostat (aint that the name of the post??)
Anyways, I bought a 180 thermo from pepboys and it was about 4 bucks. I put it in and the temp would get to about 230 and than it would come down. I thought that it was the problem with my fan so I installed a switch and I switched it on, but it did not affect anything. The temperature would still be 230 before it goes down to 170. Than I would drive to 200 and than well over 220. I was perplexed, and than one day I decided to go to NAPA and get a good thermostat. First I asked for the 170 stat, but they did not have it. Than I settled for 180 Superstat. I installed it and waited with engine idling. I looked at the temp and it got up to about 180 and than I touched the top hose and it started circulating coolant. Than I checked my guage and it was 180. My previous stat would not open untill 230 although it was a 180 stat. I was pissed. If I knew this I would have saved some money. Now my car drives between 170-190 all the time no matter the heat. My fan is almost none existant, although I still turn it on when the temp hits about 170. It does help, but not nearly as much as the stat.
So, when I first wrote this thread I knew there was something to do with a thermostat, but was not sure. Now, I am totally sure that for some of you outthere who have the problem of the car heating up over 220 and than going down, this might be the problem. Get yourself a very good thermostat, dont skipon it. As I found out its very important.
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From: Delta, PA
Car: 89 Firebird
Engine: L05 350 TBI
Transmission: 700r4-slippin' on it's last leg
Nice to hear that you found the answer to your problem, and thank you for responding with the results
. Many of these threads go unanswered, so when people do searches, all they find are dead-end threads. 
Thinking about what you've said; it might be agood idea for anyone else having a problem keeping the engine cool, to take the thermostat out and test it in a pot of water. You can heat it up and use a thermometer to test when it comes fully open.
. Many of these threads go unanswered, so when people do searches, all they find are dead-end threads. Thinking about what you've said; it might be agood idea for anyone else having a problem keeping the engine cool, to take the thermostat out and test it in a pot of water. You can heat it up and use a thermometer to test when it comes fully open.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
Defently, I just never got around testing them. One would think they come ready to go from factory. Now, if you wanted to pass emissions than you can technically use this "faulty" thermostat. Its funny since I thought I passed with a 180 thermo, boy was I wrong, more like 230 thermo!!
Anyways, I belive that many people overlook the thermostat (just like I did) and than complain about overheating problems.
Also, the fan is a big part of the cooling system (although I dissed it in my previous post). I remebered when my fan went out, the car never cooled off. So, cherish your fan/s and take care of your thermostats. They go bad or are bad much more often than a radiator or a pump (unless faulty or damaged).
Thanks.
Anyways, I belive that many people overlook the thermostat (just like I did) and than complain about overheating problems.
Also, the fan is a big part of the cooling system (although I dissed it in my previous post). I remebered when my fan went out, the car never cooled off. So, cherish your fan/s and take care of your thermostats. They go bad or are bad much more often than a radiator or a pump (unless faulty or damaged).
Thanks.
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Joined: Jan 2004
Posts: 2,322
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From: So. Ohio
Car: 88 Camaro
Engine: L98 350
Transmission: 700r4
One thing to consider is that the hotter the radiator and coolant, the higher the efficiency. Consider that with a low temp thermostat you are at 180 degrees, the outside air at 80, you have a 100 degree differential. If you are bone stock you probably would be running at 220 degrees, thats a 40 degree increase and around a 40% higher differential. This (hotter temp) would give a dramatic increase in efficiency for the cooling end of the cycle. If you have a marginal system to start with, it would be tough to maintain 180 without a better radiator or more powerful fans.
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From: colorado
Car: 1992 Trans/am convertible
Engine: 305 TPI
Transmission: 700r4
Axle/Gears: 2.73 drum WS6
How about a high flow bosch pump, and a brand new radiator. New hoses new thermostat, re-built engine... I see what you are saying, but I am not sure if its right or not. I heard many different things and came to a conclusion that the only way for me to find out is to do it. You see, on my machine I went through a lot of things untill I figured out what the problems were. First and foremost you have to have the airdam to have any kind of consistency in cooling (not to mention lower temps). Also, I figured that the lower thermostat should lower the temperature of your vehicle. Now, Firebirds are computer controlled (except carbed ones) and to lower the temperature you would need to modify the chip. However, there are way too many people out there running stock who have changed the thermo and their temperatures are a lot lower. This goes to tell me that computer controlls so much, than physics and chemestry along with common sense get into the picture.
Now, I am no pro at cooling by anymeans. I am just an average Joe who is trying to get his ride going and make it really nice. Does this mean that I might become a pro at it?? Only if the cooling system makes me more problems.
Anyway, I am not trying to contradict anyone, rather I am trying to get the **** straight since I keep getting a lot of peoples takes on how cooling works.
The thermostat worked for me, and thats all I know, the best thing would be for anyone to read up on this stuff and experiment.
Good luck.
Now, I am no pro at cooling by anymeans. I am just an average Joe who is trying to get his ride going and make it really nice. Does this mean that I might become a pro at it?? Only if the cooling system makes me more problems.
Anyway, I am not trying to contradict anyone, rather I am trying to get the **** straight since I keep getting a lot of peoples takes on how cooling works.
The thermostat worked for me, and thats all I know, the best thing would be for anyone to read up on this stuff and experiment.
Good luck.
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