Swapped my LG4 for a 350 this weekend, and on my way to work I was constantly watching my gaudges and noticed the temp was running between 220 and 230. Surely this isn't normal. When I got home I tried playing with the timing a little more since it was still a bit rough. While I was doing this I left the radiator cap off and had it idling for atleast 45 minutes to to if maybe I could get some air out. The whole time the temp only reached 190-200. After that I put the cap on and drove a couple miles away to see how hot it would get. Once again it stayed between 220-230*. What is the problem? I have 160* stat in the 350 that was in the 305 only a few weeks. The 305 ran between 190-180 about. Can anyone help with this? Could the timing cause that much of an increase? I put in a Crane Compucam 2040, could this cause it?

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1984 Z/28
Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Hypertech HEI, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's
*Have 350 crate getting final touches.

 

I had almost the same problem a while back. At idle and really slow speeds it stayed around 220* or so which seems to be normal around town. When i started really driving around above about 30mph or so it got really really hot. Especially on the freeway. It turned out that one side of my airdam on the bottom of the car had come unbolted and was being pushed back by the air, so not much was going to the radiator. i replaced the bolts up front so that it stays in place and it helped a lot. They do run really hot though unless you rewire the fans to turn on at a lower temp. From what ive heard it doesnt do any good to have a low temperature thermostat otherwise.

 

The airdam is one thing I did check for and its still there nice and secure. I don't have an electric fan, I have the same belt driven clutch fan. Does anyone know how to really bleed the air from the cooling system? I have a feeling there is a bit in there.

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1984 Z/28
Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Hypertech HEI, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's
*Have 350 crate getting final touches.

 

Tell us more about your cooling system. Maybe your clutch fan went bad when you had the engine out. Also, have you tried flushing out your radiator? Maybe it got a little clogged having the system apart, a few others have ran in to similar problems when changing heads and engines. When you are idling your cooling requirements are more reasonable. What are you running for heads and head gaskets on the 350? You may try a 180 thermostat. It is possible with a 160 to circulate the water too fast increasing temperature. The 190-200 regulation temperature sounds a little high for a 160 thermostat. It sounds like the thermostat is always hanging open for its dear life, when its idling the heat production is less so the temperature is lower. When you get under way the heat production is higher and the temperature goes up. Check to make sure your air dam and fan shroud are in place and in reasonable condition. Then check to make sure you have a good wind pulling through your radiator. Cigars work good for this.

 

Some people drill one or two 1/8" holes in the thermostat to help let air back out. I usually fill the block through the thermostat housing before putting the thermostat back in. You can also crank the engine with the radiator open and wait for it to get hot enough to open the thermostat. When that happens it will suck down the water if it has an air pocket. Then fill it up and close off the system. By now though if the system still shows as full it should not have any bubbles in it.

 

The fan shroud and airdam are good to go. They are on eof the first things I checked for. The motor is a stock GoodWrench 350 with stock cast iron heads. When I pulled the 305 I pulled the radiator out and flushed it a good 15 minutes from both hose mounts and the filler hole. I had good clear water coming out for atleast 5 minutes before I decided to stop flushing it. What might clog it while it was sitting? The stat being too low makes since. When I ran with the cap off it never dropped in fluid level. Does this mean my system is clear of air? It ran a atleast 45 minutes in the garage at idle. Is there anything else I should look at before I try the stat? What degree would be better for this motor if a 160 is too low?

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Hypertech HEI, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

If the clutch fan took a dump, wouldn't it just be free wheelin there? I noticed blowing an awful lot air on me while I was messing with the timing.

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

All the air is out of your system now. If it persist, then either use some water wetter, or do a manual fan switch to turn on the fans with the flip of a switch. My car never sees 195 on 100 degree day with the a/c on in traffic. All stock cooling system, but the water pump which is high flow. Remember also that your radiator was for a 305 originally, and not the bigger, hotter running 350. That may be it as well, but I still have my stock radiator size with my setup. that should help some, but make sure it isn't timing related due to the rough running you were talking about.

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1984 L69 Z28 with 350 H.O., Hypertech ThermoMaster Chip w/ 160* PowerStat, Stock L69 Dual Air Intake w/ K&N, L69 Dual Plane Intake Manifold, Modified Q-Jet, 350 4 bolt main w/ Crane Energizer Cam & 1.5 Roller Rockers, Lunati Drop Forged Crank and Rods, 23 Degree Trick Flow Heads, Hooker Comp Headers, 3:73 Posi, T-5 (Soon to be a T56!), 4-wheel disc brakes, 3" Catback Exhaust...etc.

Wise man say....Man who jump on bedspring this spring....have offspring next spring!

 

When I swapped the motor the coolant sensor from the 305 was too small. The fella at the parts store give me one for an 84 GMC pickup. Aren't all coolant sensors created equal? If not, does anyone have a part number for the right one?

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

I forgto to mention in my last reply that I replaced the thermstat with a 180* and it ran the same. It just didn't take as long to get to 230 this morning.

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

You might want to check the water pump flow and coolant hoses. If you can see flow in the radiator tank at an elevated idle, your pump should be adequate. It the lower radiator hose is collapsing from pump suction at road speeds, you could have inadequate flow.

You may also have an exhaust restriction, late timing, or inadequate air flow through the radiator. You might also be reunning excessively lean at highway speeds. Any of these factors can contribute to overheating.

Later,
Vader

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"Stop it - or we'll go blind!"

 

I had a 1983 Z-28 with an LG4 engine and mine also ran hot. Sometimes it would get up to 260 degrees. The problem was that cheap, tiny one core radiator and half fan shroud that they had in the car. I replaced the radiator and fan shroud with the 1984 L69 components, and the car never ran hot again. It would stay at whatever temperature the thermostat opened at.

 

Here is my 2 coppers...

220-230 is about average for a 350 in the third gen cars.

With the cap off the coolant mixture sublimes and boils off and the temp will hold just under 212ºF. With the cap back on there is pressure placed upon the coolant mixture and this increases the boling point.

My yes, timing can cause havoc with the temp.

The one thing I don't remember is if you had a elec. fan or mech.?

Also, you may want to look at the tranny. I've seen a couple of cars start to pop temp.s after swaps due to the increase in tranny temp. You may want to swap the fluid to be on the safe side. Good luck.

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Illiterate?
Write for help...

 

Well, I can now rule out the timing. I just changed my plugs and came to find the ones in there to start where a lot hotter than the new ones. This smoothed the idle right up and killed the vibration when I accelerated. I looked close at the temp when I drove it and still it persisted to run 230. I'm still not sure about this coolant sensor. Is there any easy way to get an accurate reading on the temp just to see if the gauge is off or not? Red Devil, I still have the mech fan. Does a 350 really run 40-50 degrees hotter than a 305?

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

Is there a size difference between the 350 Camaro's radiator compared to the 305 Camaro's? I found a new radiator for a VIN 8 Camaro for $150. If this one is bigger then I will go ahead and get it. I have nothing else to look at. Everything else in the car is new or working like new.

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

Z/28.
The TPI cars are notorious for running at high temps with the electric fans. The mech. fans I have not seen as much of a problem. Have you replaced the fan with a flex fan? If not have you checked your fan clutch? Is there a good seal at the shroud and is the clearance correct for the fan to shroud?
I think that the radiators were the same, but I don't have a part numbers in front of me so I can't say with certanty.

Why have you ruled out your timing? Also, to verify the temp you can buy a cheapo temp gague at walmart for $12 and hook it up to see what that reads. Make sure you use the supplied sender. Good luck.

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Illiterate?
Write for help...

 

was the coolent sensor for an idiot light or for a gauge? There is a difference. Also did you store the clutch fan upright while the swap was being done? Laying them on there side will damage the viscous clutch.

 

I told the fella at the parts store it was for the gauge, besides that, I e-mailed SDPC tech department witht the problem too. I give them the part number of the sensor in there now and they said it was the correct one. This is all they said. They informed me that Camaros in 84 didn't come with a 350, like I didn't already know that. I shouldn't say I ruled out the timing, was I meant was I can rule out the rough idle. I changed the new plugs and wires with newer plugs and wires, now it idles a lot smoother. I really do appreciate everyone helps. I hope I can finally come to a bottom line on this problem.

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

Z/28cwby, look I don't think it is your timing and if you did what Vader said and it was ok then I think it is your fan.
I think corredt me if I'm wrong guys but all 350's (at least TPI) had the two electric fan setup. The clutch fan does not ssuck as much air thru the radiator as the dual electric fans do. And the fact that you have a 700r4 tranny (and do you keep it in OD) at low rpm's the fan may not be sucking as much.
Now there may be guys with a 350 clutch fan and the engine temp is normal (180-220) and if so please reply so he doesn't go out and waste his money on the electric fans!
I don't think it is the cam you put in cause I have a ZZ9 cam and I run at 180* without air and around 210* +/-10* in the city with air.
I hope this helped you and others either prove me right or wrong about the fans.
Good Luck!



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89 IROC 350 Auto
Air Foil
TPIS Underdrive pulleys
K&N Air Filters & Mods
Modified MAF and screens removed
Ported Plenum
Edelbrock TES Headers
TRUE DUAL Exhaust
Edelbrock Performer Aluminum Heads
ZZ9 Cam
TPIS Level 5 Chip
2200 Stall Converter
2.77 Rear Gears(gotta get 3.73)

 

What your trying to say is, 350 and 305 mechanical fans have different cluthes? I did not know this. What would be better, a 350 clutch or a clutchless flex fan? Or would I be better off all together to drop the mechanical fan and run dual electrics? Or, a buddy if mine has a clutchless flex fan, and a small elec. fan mounted on the front of his radiator. It seems to keep his 60 over 350 under 200 on this 110* central valley days. What do you fellas think?

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

Thats my preferred rig. Good solid radiator, heavy duty flex fan in a shroud, and a small assist pusher electric fan for those traffic jams. Sure its possible to keep a 350 under 200. Something has gone wrong for you, either your radiator and fan aren't getting the job done or the engine has blown a head gasket or something. I wasn't aware the 350's had a different clutch than the 305's. They may have had more fan blades but as far as I knew GM used the same clutch in all the cars.

 

I also did the 305 to 350 swap and Mine stays constant around 220-230. Now I do have a broken head wich I think is contributing to the heat problem. But beyond that I have the same ole 305 Fan Clutch. THere is no difference between 305/350 fan clutches.

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John Chamberlain
1984 Sport Coupe Camaro, 1979 350. Dynomax 2 3/4" cat back single in dual out muffler. Saving for Headers, Heads, And new Intake. Then.... PAINT




[This message has been edited by 84FBODY (edited July 14, 2000).]

 

I don't know if the clutches for the fans on the 305 and 350 are different. But I do know the electric fans do have a higher cfm rating than 1 clutch or clutchless fan. Going to add a electric with the one you have would be better.
OK?
Good Luck!

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89 IROC 350 Auto
Air Foil
TPIS Underdrive pulleys
K&N Air Filters & Mods
Modified MAF and screens removed
Ported Plenum
Edelbrock TES Headers
TRUE DUAL Exhaust
Edelbrock Performer Aluminum Heads
ZZ9 Cam
TPIS Level 5 Chip
2200 Stall Converter
2.77 Rear Gears(gotta get 3.73)

 

Well, I got a 16" electric fan from PepBoys. It has a 1250 cfm rating. I'll go ahead and sqeeze that in front of the radiator. Lo and behold, SDPC e-mailed me back a bit ago and informed me that if I didn't do anything to my carb, then it is more than likely running to lean (As Vader had mentioned too). He gave me part#7033812 for a set of metering rods that GM sells for carbs when swapping from a 305 to a 350. Why couldn't he have told me that two days ago. Now I have to wait till monday for the dealer to open. He also answered my radiator question. He said he wasn't sure of the difference, but the 84 vin H and the 92 vin 8 have different part numbers, 03049566 and 52453958 respectivley. I'll put the elec fan on and see if this helps any over the weekend. If not, the only other possible thing would have to be the carb being too lean. I have tried every tip you guys have offered. I really do appreciate everybodies help here. I hope I can return the favor soon. We'll keep trying.

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

The radiators are different because a Vin H engine has both heater hoses on the engine where as a Vin 8 engine has one heater hose on the radiator and one on the engine.
That's the only differance I know of for sure.

If you were to buy a $150 parts store radiator you will get a UNIVERSIAL radiator that has provisions for trans cooler and heater hose but they will have plugs in them, just remove them if you intend to use those feature.

If you buy a dealer radiator you will get exactly what you ask for depending on year.


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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Trick Flow Heads, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine belt setup.

 

I installed the elec fan last night in place of the stock mechanical fan. After a bit of a slip with the trans line being loose and making a mess of things, I finally got to try it out today. At about 1:00 and the tempature outside being a little hotter today than yesterday, it got just above the 220 mark. The past few days it has been at the mark between 220 and 260 (about 240 to my guesstamation). I'll get the new metering rods from the Chevy house on Monday and see what happens then. I also put the 160* stat back in it. When I replaced it a few days ago with the 180* is when it starting running close to the red line. Atleast we're getting somewhere now.

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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

did anyone mention the radiator cap can cause some screwy crap to go on?

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89 5.7 IROC
13.7 @ 99.7
1.96 60ft

 

HEEYYYYYYYYYY

Sorry, had to get your attention. I had the EXACT smae problem when I switched from my LG4 to my 350 acouple of months ago. I went through everything from head to toe. The part I really didn't like is how hot it "got" on the interstate. THE PROBLEM IS YOUR GUAGE!!!! The temp sender out of the 305 did not fit in your head because it is smaller, correct? So, youwent and bought a bigger one that did. I don't care what anyone says, it does NOT work with our guages. After deciding that I did not think that my car felt as hot as the guage always said, I tried a good aftermarket guage. Voila!! It runs at 160 with a 160 thermo, without the electric fan on unless I am sitting in traffic all day. When i get on the interstate it levels out at a nice 180 without the fan. I am 99.9% sure this is your problem. Believe me, I went back and forth 100 times with different things. That guage is wrong.

What are you waiting for?? go get a new guage and enjoy your cool running new 350!!

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1986 yellow Z
pics of my Z:
Camaro1 Camaro2 Engine
More at: My Directory
Email: MeanYellowZ@hotmail.com Aol/IM: RCY1980
Owner of the Camaro 9 out of 10 Thirdgenners approve of, part of the non-existent Iowa crew.

 

Problem solved. went to Pep Boys and bought a $15 gauge. According to the cheap guage, I am running just under 190* around town. she drops down to about 170 on the highway. Thanks for all the help fellas. Hope I can return the favor soon.


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1984 Z/28
GoodWrench 350, Edlebrock Performer intake, MSD 6AL Super HEI kit, Crane CompuCam 2040, Edelbrock headers, Catco cat, Flowmaster aftercat, K&N, Custom 700R4, B&M Megashifter, Eibach springs, KYB GR-2 struts/shocks, Jegster adj LCA's, Lakewood adj panhard bar, BFG Comp T/A's, 160* stat

 

Sigh, phew. Glad to hear that. Always nice to read a story with a happy ending. Naturally we all contributed not holding you to any kind of a debt, but any time you have words you would like to share fire away.