FreeSpirit

Honestly I can't really tell if it's really overheating or if it's the sensor messing up like the gas tank sensor does from time to time. But I don't think the sensor is messing up because when it starts up it stays low, and even for the first 15 minutes of driving (after warming up for 2 minutes) it'll stay OK. But the engine bay doesn't seem too much hotter than normal, other than the radiator hoses which are very hot.

It only overheats with a lot of idling, like in a lot of traffic. Usually will go to 3/4 without the heater on. Stopping and letting the engine cool off doesn't help much, it helps more to drive fast on a freeway with the heater on.

It hasn't been too bad until yesterday, I was in a lot of traffic in a lot of hills, an it went WAY past middle. So far past it was very close to the red, and I couldn't get out of traffic so it ended up going in the red for about 5 minutes. I was very surprised nothing happened. The engine seemed a little weaker, like 2k rpm was not as strong as usual, but other than that it seemed fine.

History:
I have replaced a lot of stuff in the past 3 months, water pump, thermostat, radiator, hoses, etc. I had a problem with it overheating after my 2nd coolant flush. https://www.thirdgen.org/forums/tech...hot-after.html It turned out to be air in the system. I burped it out and it ran fine after that, although slightly hotter than before (like the tiniest nudge on the meter). I also messed with my coolant overflow tank during the 2nd coolant flush. It was dirty, so I replaced with a generic one and I still haven't gotten a new stock overflow tank. It seems to be set up right though, I've had a few mechanics tell me it's fine.

Also, the coolant keeps turning rusty. After the first coolant flush, it only took a few days for it to turn from a fresh green to a rusty ugly color again. Same thing after the second coolant flush. Oil level seems fine, it's been at full since my first tuneup. There is no smoke coming from my exhaust. So I don't think there's any oil burning. Coolant seems to stay at the same level (checking when the engine is cold), so I don't think there's any coolant leaking. Although there was a time when it seemed like there was less coolant than the last time I had checked. However, I was checking when the car was hot.

This recent overheating problem seems to have started after my mechanic friend replaced the EGR valve. Also, (this is very sporadic and rare but it's worth mentioning) there is sometimes an ugly smell since he replaced it. I have an exhaust leak, and it's not the same smell as that. It smells like gas, but just uglier dirtier gas. Is it possible air was allowed back into the system in the process of replacing the EGR valve? Also could it be the generic coolant overflow tank? There is a top hole which is unplugged and open, while the little plastic tubing goes to the bottom hole. The stock coolant overflow tank only had one hole. The coolant tank seems leveled, so I don't think it's that.

Maybe there is something electrical? Recently a fuse went out and the rearview mirror light, door lock buttons, and cigarette lighter had gone out. Replaced it and it's fine now. The gas tank indicator has always been squirrely since I got the car. It works fine, but sometimes will move to a quarter tank less than what is actually in the car. Taking a hard left brings it back to the real level, or eventually it will just creep back to the normal level.

This is the thermostat I replaced the stock one with:
http://www.oreillyauto.com/site/c/de...&keyword=15359

Not sure what temperature rating it is

W.E.G.

It's not overheating if its not blowing excess coolant into the overflow tank.

Fresh coolant that quickly, and repeatedly, becomes contaminated suggests a head gasket failure. This type of gasket failure may contribute also to an overheating problem as the hot exhaust gas is introduced to the coolant.

FreeSpirit

I thought there was white smoke when you have a blown head gasket? Because of the gas mixed with the coolant

It's not blowing excess coolant into the overflow tank. I think it is a sensor or something. Today it was fine pulling up to the gas station, then I pumped gas, and it was at 3/4 when I turned the key halfway. Then when I started it stayed at 3/4 for only about a minute before going back to normal. I turned the heater on right after starting the car, and the engine was clearly not hot. Maybe it is the thermostat and it was just a crappy thermostat.

FreeSpirit

Well today it overheated on the freeway after pumping gas. Smoke came out and Im sure its dead cuz it turned off on me. It drove fine yesterday for a good 3 hours total. I drove to a house, to get food, gas, and then went to a bar at night.

What do you think happened? And what should I check? The engine was smoking for a good minute or two and it was overheating for a while. Hopefully the tranny is good. Is 700 for a rebuilt engine a good deal? From a pro mechanic, not including labor to put it in

ibmtech

iTrader: (1)

I am not sure of what a pro mechanic is ? But if that engine is in good shape and running, that isn't bad..

FreeSpirit

Well the engine isn't actually dead.. It was just way too hot. After a few hours, I put some coolant in it and started it. It overheated in about two minutes though. Went almost to the red so I turned it off.

There is a coolant leak that happened after it overheated on the freeway, it looks like from the coolant plug, on the bottom. Or somewhere on the bottom part of the radiator.

When my car seemed to be overheating after pumping gas (this most recent time), I tried to turn on the heater, but it only blew cold air. So I thought the sensor was just going wacky since I had just pumped gas. (It's weird the car overheated quickly after pumping gas twice recently, but was fixed by turning the heater on). But when the engine was smoking and everything, the heater still only blew cold air. My friend told me if my passenger carpet was ever wet, my heater core probably blew. It was wet a while ago, like a few months ago.

So I'm hoping it's just a bad radiator. It's a Murray Heat Transfer 433918, got it from Oreillys. Replaced the stock one with it about 3 months ago. What kind of radiator should I get? When researching Murray, I read bad things about the only cheap radiator I can find (Vista Pro Ready Rad).. I don't really want to spend 500+ on a radiator when I'm not sure what the problem is yet. It seems like a bad radiator caused it though. I'm not sure if Oreillys will let me get a new radiator, and I would still need a new one since I'm not gonna trust the same brand.

I meant someone who does it for a living, not just a hobby.

Jersey89GTA

iTrader: (1)

You should really have it checked out by a mechanic before you cook the block and warp the heads.

My take is a head gasket, freeze out plug, t stat wrong or bad, something ain't right. Throttle body has AF going thru, maybe gas is mixing there and getting sucked thru the intake.

?? Have it checked out, let us know what you find.

FreeSpirit

My friend is a mechanic and he doesn't know yet.

Yeah it's running. And maybe gas is mixing there because there's an exhaust leak or some kind. You can hear it. And I have an xstream air cleaner lid, the one with an air filter on top. My friend has been telling me for a while that I should just use a regular closed one.

Pat Hall

iTrader: (31)

Since it cools down when you're on the freeway, I doubt your radiator is bad. I have to agree with the other guys and say you've either got a malfunctioning t-stat or a head gasket problem. When you said you were getting nothing but cold air with the heater on, that can be caused by a stuck t-stat, which also causes the motor to overheat real quick. Btw, if your heater core is blown, have fun with that. Heater cores are a royal PITA to replace! I'm sure you've probably already checked this, but I didn't see you mention anything about your cooling fan. Is it turning on around 220-230 degrees? A bad head gasket could also explain why your coolant is getting murky and dirty so fast.

naf

iTrader: (7)

First thing is to pressure test your cooling system. A leak is the most likely cause of overheating and failure to blow hot air from the heating vents. You can take it to a shop and get it done fairly inexpensively or borrow the equipment from someone. Don't worry yet about blown head gaskets and the like. Spend your efforts methodically determining the actual problem.

The regular parts store radiator should be fine for your application. Shouldn't have to run much more than $100. Check the warranty on yours and replace it only if it's the source of the leak.

If your heater core is leaking, the pressure test will tell.

If you haven't replaced your heater hoses (2) and your upper and lower radiator hoses with the new radiator the TGO Gods are likely frowning down upon you.

Do not trust that wavy thing in your dash to give you an accurate reading of the state of nature at the end of its sender. It's notoriously inaccurate. Note where it normally is and only worry when it reads way off from normal.

Donnie(91rs)G

Its neg 25 degrees today here in iowa and somehow my car managed to almost over heat wtf?! I drove to school for about 7 min and my car was reading almost 230 and I have a brand new thermostat and hoses and have never had a problem before so what could have happened? Please help! I have work tonight and need to get this fixed! And also I had no heat? Motor was blowing but it was ice cold

Richboll

Check your coolant level when the car is cold. It really sounds like you have a leak. If your coolant is low you have a leak and will need to fill it everytime you go to drive the car until you find the leak. If it's full, then see all of the solutions that have already been mentioned for the answer to your problem. Start with the simple ones and progress from there. Good luck!

Donnie(91rs)G

There's no leak, I park in a finished garage and there's no puddles, a kid with a t.a at school had the same problem today and we figured out his coolant is frozen and I think mine is too

naf

iTrader: (7)

Most likely cause of no heat and high temps is loss of coolant. Especially if it came on suddenly. A bad tstat can cause the problem but this is somewhat rare.

naf

iTrader: (7)

Ooof. Antifreeze in coolant provides two valuable functions. It prevents freezing of the coolant (which can and will split coolant hoses, destroy your radiator and crack you engine pieces). It also provides corrosion protection by increasing the pH of the coolant. The disadvantage that antifreeze does not provide the same cooling properties as water (it's slightly less effective) are greatly outweighed by these benefits.

Leaks may not be readily apparent when the system is not under pressure. It is also harder for a system to leak once all, or most, of the coolant is gone.

Donnie(91rs)G

yea i checked my coolant and its not frozen in the radiator but the overflow tank is frozen, and my lines running to my heater core are frozen

naf

iTrader: (7)

Time to flush, add antifreeze then check for leaks and busted stuff.

Richboll

Water doesn't work very well as a coolant in below freezing weather. Get it in a heated area or do whatever it takes to thaw it out. As someone born and raised in Wisconsin, I know for a fact that freezing water can and will crack an engine block. And they're not called freeze plugs for no reason. Always run at least a 50/50 mix of anti-freeze and water and check it before cold weather gets there. Coolant isn't too effective when it can't circulate.

Donnie(91rs)G

thing is, i just flushed coolant and put new hoses on, new t stat and it was 50/50 coolant mix, im afraid im going to find something bad when it thaws

1984 Z/28 camar

Does your car have the air dam. It pushes the air up from the ground and through the radiator. do you have an electric fan or mechanical? If you have a electric might be a bad sensor. The car should have a overheat cutout that shuts the car off before any damage can be done. But that doesn't always work.

Richboll

Did you use the pre-mixed 50/50 and then add water or did you go with the straight anti-freeze and then add water? I've never had a problem with adding one complete gallon of straight anti-freeze and topping it off with water. You also need to invest in an anti-freeze tester. Even a simple one like this can tell you to approximately what temperature you are protected to.

http://www.oreillyauto.com/site/c/de...0185&ppt=C0075

Jersey89GTA

iTrader: (1)

Second that - get a tester, when you flushed, you may have had trapped water, and 50/50 added along w/trapped water = 60/40 or 70/30 which has less freeze protection.

Could the tstat been put in backwards ? Pull it and test it in a pot of hot water.

Water pump not working. You got to see if the AF is flowing... Cut a tee in a heater hose w/ valve to open and close, once its up to 180 it should be flowing.

1.Thaw out the car (somehow)
2. Pull and replace the stat - cheap/ end mystery
3. get AF tester, check freeze and boil protection of exist AF,
4. get some pure AF to richen it up if necess

I personally think its the stat, if the heater hoses aren't getting hot, then AF isn't flowing. Bad stat or in backwards.

Let us know.

Jersey89GTA

iTrader: (1)

Second thought - and you haven't mention it ...

Does the electric fan kick on ? (Only one will come on on driver side, other side is w/ AC compressor) Comes on at 227 deg. My car will read about 232 ish with fan cycling on/off on the gauge. AF boils at around 235.

Air dam - as questioned above ? When driving, mine will stay at 180 all day long while moving. If yours off, it will affect cooling, especially if fan isnt working.

FreeSpirit

Well thanks for taking over my thread, but anyway..

I finally got some work done on the car. Replaced the radiator and thermostat (180 instead of 195 now, it runs a little cooler). Filled it up with 1 gallon of Prestone antifreeze, and the rest water (I know this is a 1/2 mix but I thought I had more antifreeze left). It runs fine when moving, even in some light city driving, but when idling it slowly overheats. It slowly went all the way to the red. Yes it's really overheating, antifreeze/coolant boils, steams a little, rises.

The electric fan does not seem to be working anymore (it definitely used to work about a month ago, at around 3/4 of the temp gauge). I recently replaced the fuel pump relay and the fan relay (well whatever other relay is exactly the same as the fuel pump relay, and right next to it). However, I don't think the fan is the problem, because when I first had the overheating when idling problem, my fan was working. But I would also like to know how to fix the fan too.

Oh yeah my heater core is fine, my heater works perfectly now.

We believe the problem was a faulty radiator, which caused a slow coolant leak (we looked many times for leaks but never saw any though), which then caused it to overheat on the freeway. But something is still wrong obviously, because it overheats while idling.

My friend thinks it's the temperature sensor? I think he means coolant temperature sensor? Can I test this somehow? If I replaced it, do I need to buy both pieces, the sensor and the wire connector piece (sender)?

Oh yeah, and the oil level gauge goes all over the place. Doesn't constantly move, but every once in a while will move to a completely different level (either higher or lower) than before. Like I said before, gas tank gauge has always switched from the actual level, to 1/4 above what it actually has, every once in a while. So that's another reason my friend thinks the temperature sensor might be bad. But I don't think it's bad because when it says it's overheating, it really is overheating (coolant was boiling and rising)

wbstearns

dont trust your factory gauges too far as they are obviously having problems and my money would be on your cooling fans being the current culprit my blazer has same issue because i dont have a fan shroud (mechanical fan)

naf

iTrader: (7)

The fan relay should have four leads going to it. 2 larger gage wires: one constant 12V and the other to pass power to the fan motor. 2 smaller gage wires: one 12V with ignition in run and the other to the temp switch in the passenger side head. The temp gage has NOTHING to do with the operation of the radiator fan.

1. With the ignition in 'run', ground the temp switch lead (that's what the switch does: closes a circuit between the lead and the outer jacket of the switch-engine ground). The fan should run with the lead grounded. If it does not:

2. Verify that the relay is getting constant 12V (just check both larger gage leads, one will be constant 12V). Yes go to 3. No trace the power lead to the starter terminal and check the fusible link.

3. Verify that the relay is getting 12V with ignition in 'run' on the smaller lead that is not going to the temp switch. Yes go to 4. No chase it down.

4. Verify that the relay is passing 12V to the fan power lead. Yes go to 5. No replace the relay.

5. Verify that the fan power lead is passing 12V to the fan motor. Yes go to 6. No chase down the wire.

6. Verify that the fan motor lead has good ground. Yes go to 7. No trace the ground lead (other wire in two wire connector to fan motor).

7. Replace fan motor.

In my experience it is seldom the temp switch or the relay and usually the fan motor that fails. When it fails it may blow the fusible link on the power wire from the starter terminal.

Richboll

It does sound like the fan isn't working. That's exactly the kind of symptoms I had when my fan quit working. Go through the steps outlined by naf and it should determine if that is your problem.

Oh, and its not an oil level gauge, it's an oil pressure gauge and it will show different pressures as your oil is cold and then hot. Although it does work like an oil "level" gauge when your oil is low.

Pat Hall

iTrader: (31)

Yeah, even though you said there was other things causing it to overheat before when the fan was still working, if you have no fan running when the car is sitting still and idling, it's guaranteed to overheat in a hurry! When sitting still, the fan is the only way any air gets pulled through the radiator. My fan hardly ever comes on going down the road, but as soon as I get in stop and go traffic, it comes on very consistently. Naf's checklist is a good way to diagnose everything. When I had my TBI motor, I found the most common thing that caused the fan to fail is the mickey mouse wiring and plug that connects to the switch in the passenger side cylinder head. It's so close to the hot exhaust manifold that it commonly gets melted. That's an easy place to check if the fan motor is working also. If you ground the wire that goes to the switch in the head, the fan motor should turn on. I had almost 300K on my original fan motor and it never went bad. With my new motor I ditched the crap, factory setup and went with the Hayden adjustable fan control. Getting rid of that fixed temp switch in the head was the best thing I ever did! Anyways, back on topic, getting your fan running again should be your 1st step. If it's still overheating after you fix that, then proceed from there.

naf

iTrader: (7)

Rock Auto had a replacement pigtail for the stock temp switch on close out recently. Now the only one I see runs +$10 (it's the same connector used for the KS). At that price I'd probably go with an aftermarket temp switch for a lower setting. Most of those use a simple spade connector.

I've also used the variable fan switch with the sender in the radiator. Use it on a dual fan setup as primary, stock setup as higher temp secondary.

Pat Hall

iTrader: (31)

Hey Naf, not only did I install the Hayden fan control, I also replaced the stock dual fans with the Taurus 10 blade, single fan. It cools leagues better than the stock dual setup ever did. Never had a problem with overheating with the old TBI motor and the stock fan, but my new motor simply wouldn't stay cool in the summer until I upgraded everything. With the Hayden setup it's nice having the temp probe in the radiator fins instead of right next to the exhaust manifold, and setting up my cooling system for summer or winter only requires a simple adjustment of the screw on the aftermarket fan control. A lower temp fan switch is a good idea for summer, but then it ran too cool in the winter. Adjustable is so much nicer.

naf

iTrader: (7)

I like the dual fan system, primarily for the redundancy. I burned up a fan motor on my 85 TA while traveling once, August in SC. There's a little peace of mind knowing that if one system goes down, you still have the backup. The single fan did fine otherwise.

The Taurus system is supposed to be a good upgrade though.

FreeSpirit

Thanks for the list. I'm so close to fixing the problem. I replaced the coolant temperature sensor, and that wasn't it. I used a voltmeter and this is the most I tracked it down:

There is 12V going to the relay, and the relay is brand new (bought last month). Resistance reads 65 ohms.

However, there is no power coming from the fan power lead that connects right at the fan. So I checked 5 but did not check 3, 4, or 6. I don't know where exactly to check for those. I think it's in the heat shield / wire insulation.

Still have not checked the fan switch between the 6 & 8 plugs. I know the gauge is fine though. When I turn the A/C on, the fan does not come on. I do hear some fan or something, coming from near the A/C compressor, but the radiator cooling fan does not come on.

Also, one thing that's weird is that the coolant in the overflow tank is all rusty brown already, even though we just put the coolant in a few days ago. However, when I changed the coolant temperature sensor, it was definitely bubbling some nice green coolant. What does that mean? The cap was replaced 3 months ago with the first radiator. Maybe I should replace it again too?

Pat Hall

iTrader: (31)

Once again, the next thing you ought to try is grounding the wire that goes to the fan switch in the cylinder head. If that doesn't turn the fan on, the next thing I'd do is fabricate 2 wires, plug them into the fan motor and hook the other ends to a battery charger. If the motor doesn't work at that point, then you'll know for sure that the fan motor itself is shot. Hey Naf, I wonder if the 85 style fan motor is any different from an 89 one, because my 89 TBI single fan motor had close to 300K on it, and still ran just fine. Can't really say yet how dependable the Taurus fan is, cause I've only had it in there for about a year so far.

naf

iTrader: (7)

The fan motors should all be the same, even the dual fan systems use the same motors. My 85 was converted to electric fan several years ago. That was a failed replacement motor with maybe 80K on it. I've had a few motors fail over the years on different cars. Never an electrical part failure aside from a loose or broken connection.

rffanat1c

Not sure if this problem occurs in a dual fan setup, but my 84 Z28 fan shroud warped causing the fan to not turn and causing the car to overheat. I replaced radiator, thermostat, hoses, and bought a new block temp sensor all unnecessarily. A real simple way to test your fan is to take it apart, take the blade off, leave the motor plugged in and turn your A/C on to max. If it turns on, all wiring is good and its something else. If it doesn't work you got a relay or block sensor issue or a bad motor.

FreeSpirit

The fan motor is good, I hooked it up to a battery and it turned out and spun. There must be some kind of wiring problem. It's somewhere in the wire loom, I'm sure, since the relay is good and there is power going to the relay.

How can I wire a manual switch for the fan, safely and properly? I'm assuming I need to wrap the wiring in wire loom that protects it from the engine heat. Seems simple, just installing a switch in between the battery and the fan. I rather not pay a shop for hours of labor to find the wiring problem until I can afford it. I have some other problems I need to fix too, so the more money I can save for now, the better. I will of course get it fixed to stock when I have the money.

naf

iTrader: (7)

You don't want to run a switch from the battery to the fan. The start up load on that is more than 20 amps. The heavier gage wire and switch won't be cheap, especially if you plan to run it through to the interior.

The right way to do it would be through a relay, but you've already got one of those that is functioning and the proper size.

Best to find out what the problem is and fix that. Don't start hacking, it'll only cost you more in money and headaches.

Pat Hall

iTrader: (31)

Yeah, if you want to install any kind of toggle switch, avoid doing it on the positive wires. The best thing to do is install a toggle switch on the ground wire that goes to the fan relay. If I remember right, the ground wire is green with a white stripe. Install your toggle switch in that wire coming from the relay, then cut the other end and crimp an eyelet on the end of it, then use a small self-tapping type screw and bolt it to some clean sheet metal. Every time you turn on the toggle switch and ground the relay, the fan should come on, and since it's on the negative side, there's no big power load on the little switch. That'd be a quick fix without too much hacking on the harness.

FreeSpirit

But there's no power at the wires to the fan, and I think that's part of the problem. I haven't tried it yet, but I bet if I used a paperclip to try to jump the fan on, it probably still wouldn't work. I think there's a wiring problem somewhere in one of the looms. I guess I'm just gonna have to pay a shop to find the problem and fix it because I don't want to do it and no one I know wants to either. lol

Pat Hall

iTrader: (31)

In your earlier post you said you do have power at the relay though. If that's the case, it shouldn't be too hard to get that power down to the fan. The relay always has power going to it, and it's activated by being grounded, so there's a good chance that if you ground the green/white wire at the relay your fan will probably come on. If not, it'd be easy to run a new hot wire to the fan from the relay and then install the toggle in the green/white wire. But yeah, if you'd rather pay a shop to straighten it out, I can't say as I blame you. Electrical problems are a PITA. Lol. I'm just trying to give you some simple advice from the times I've had to fool with my fan wiring, and believe me, I'm not far above you when it comes to figuring out electrical crap. Heh.

FreeSpirit

Thanks for all the help. I see what youre saying. The wire looms had me intimidated but the more I think and talk about it, I think I can work something out. Theres only 3 wires really involved.

I tried jumping the aldl port to turn the fan on. The engine light started flashing, the relay clicked, but no fan. I think its just the wires to the fan. The previous owner put a new fan connector in, maybe it went bad already.

FreeSpirit

Well guess what.. it still doesnt run in diagnostic mode, but it runs when I turn on either the heater or AC. It also runs when I take out the relay and jump the A and E wires (blk/red and red) by using a paperclip where the relay normally goes. That was actually the first way I got it to work, then I tried with the heater/ac controls, and now it turns on.

Its very weird because it was definitely not working with AC or heater on before.

I have not tried waiting til it gets hot because Im pretty sure I left the fan switch disconnected anyway. Im gonna replace the connector and fan switch anyway.

So I have no idea what caused the problem, or why its still not working in diagnostic mode, but at least I know most of the wiring is still good. I have read that if it doesnt run in diagnostic mode but runs with AC, I might need a new ECM?

naf

iTrader: (7)

I'm pretty sure the TBI fans were not controlled by the ECM like the TPI fans. Sounds like normal behavior, maybe you had a loose connection somewhere.

Richboll

Or it could be that the fan is going bad. That's the way that mine acted before the fan died completely.

Pat Hall

iTrader: (31)

Yeah the TBI fan system isn't controlled in any way by the ECM, so you probably do have a bad connection somewhere or maybe a relay that's flaky.