Car Details: 1986 Chev Camaro IROCZ 305TPI, T700R4, running Speed Density. Engine has only about 30,000 Miles on it after the previous owner put in a fully reconditioned engine.


My car always used to run around the 190deg mark all the time. Sometimes the temperature would rise in traffic to over 200 but once moving again it would fall back down to 190.

All of a sudden though the car has been having an over heating problem. If left running it will easily get to 260deg. Couple days ago I took it out for a test drive and 15 mins of driving I was over 230deg! I had to pull over and let the engine cool down with the fan turned on hood open.

So far these are the things I have checked and done:

Thermostat(160deg) I pulled it out and tested if it opens correctly and yes it did. Since I had it out I also drilled some holes into it like some others are doing also.

I pulled the radiator out and flushed it look pretty good to me and looks like water is flowing through okay too.

I removed the a/c condensor from in front of the car to see if that would help but it did not. Did not help one bit, I have not put it back in.

The temp readings I am getting are on the gauge inside my car and also on my laptop when hooked up to car so they are the real figures.

The fan works great, The air it pushes through the radiator is plenty as I can feel it blowing strong when standing in front of car.

Radiator cap I have replaced and no change was seen.

The water pump does not leak or make any funny noises. Like I said above it seems like it is providing enough flow. I might have to pull it out and have a look at it to be 100% sure it is okay.

I am not losing any water from the radiator that I can see. No leaks under the car.

The air dam is in good condition.

I bought myself a screw in compression gauge and performed a compression test today. I have only done a DRY TEST as seeing the numbers that I got were pretty good it may not be necessary to perfom a WET TEST but I might do that tomorrow anyway.

RHS head
195
198
192.5
190

LHS head
200
200
210
210

Thought it may have been a blown head gasket but the numbers seem okay.

I done the test when the car was cold, had all plugs removed, removed the BAT wire from the distributor and had the throttle wide open.

I will also mention that my car is running LEAN but it has always been running LEAN and never had an over heating problem. My BLM's are aorund the 145+ mark pretty much across the board. I will be tuning the chip very soon but I am sure that is not the problem, as it ran fine for the last year like that.

The only things left for me to do are pressure test the radiator and check the water pump if a propeller is missing or something like that.

Other then that I am not sure what else to check????

Anyway to check for a cracked head or would that show up on a compression test?

Any ideas or suggestions on what to check or have checked would be very helpful as I am beginning to hit a brick wall.

Sorry for being so long but I tried to give as much detail as possible.

 

Since you seem to have covered a majority of the items that would normally cause this, you might try the following..


First off I'd recommend flushing the entire cooling system. Not just a drain and refill. Get one of the 'kits' if you have to, also helps to use a flushing solution.

When ready to fill it back up, this is what I do, and never had a problem.

I drop a full gallon of antifreeze in the radiator, then I start the car with the radiator cap off, and fill the car the rest of the way with water, while it's running. Keep an eye on it, and the thermostat will open, and you'll keep adding water. Then when full, add some to the overflow bottle to the HOT mark.


If this doesn't help the overheating, the next logical step is the radiator. You said you flushed it...how did you flush it? You can take it to a radiator shop and have it rodded out for $40-60, but then again a brand new alum Modine 951 is less than $120, around here anyway.

If at this point, you're still overheating, and you've verified again it's not the gauge's error, I'd have to say it's the water pump, sometimes the 'fins' on the impeller that moves the water inside the pump can just corrode away over time, and no leaks, but the pump isn't able to move the volume of coolant it normally would.

Another thing to check before all this is to make sure the timing is set correctly.



HTH

 

You might have discovered the major part of the problem. The fan should not push air out the front of the engine compartment, and may be wired backward.

 

Vader,

Holly smokes that might be the problem then! I hope it is something as simple as that. It all started with my FAN REALY crapping itself so I had to replace it.

When putting the relay back together I never thought that the RED wire off the FAN would mean NEGATIVE, I presumed it was positive. Well seeing you say that the fan should be sucking air in not pushing it out the I will change the fan wires and see what happens.

Thanks for the replies I will give it a shot and post back with the results.

 

The same thing happened to me once. My problem is a cracked intake, and from the increased pressure from the leak, it took out the heater core. Hopefully it is just your fan wired backwards, but if not, these things may be worth checking.

Eric

 

LOL, amazing how you can rack your brain and it be something so simple, wow , Vader picked up on that one, great job.

If you want the fan to push air, then it needs to be on the other side of the radiator. But, just stick to having the fan reverse itself.

 

I couldn't see the forest for the trees on that one.

Nice catch.

 

Problem fixed!! Like Vader said the fan is turning the wrong way. I changed the wires on the fan and boy she runs like a dream 180F.

Thanks everyone I am happy it was an easy fix!