Hello all,

Well I just replaced the radiator (Brand new one) replaced the thermostat with 160 and still running high. The air-dam is in place and water pump works fine.

This is the thing though...
The car sitting in Park with or without A/C on stays under 180.
But driving around and driving on the freeway with A/C on it goes up to 220. I have the electric fan running non-stop now. Everytime I turn on the car the fan turns on and stays on until I turn the car off. I also added a smaller fan in front of the radiator on the passenger side w/ toggle switch. But using both fans it still gets up to 220 on the freeway.
As soon as I turn off the A/C the temp drops to 180 within 5mins.

Maybe the main Electric fan is bad? It's the original one. (92 camaro TBI 305)
Can anyone help?

Thanks,

 

i was having the same problems with my car and i figured out what the problem was. first i had a pressure test done to find out if there any leaks in the system that i couldnt see. The mechanic pumped up the pressure and sure enough we found several pin holes in some of the gaskets. The holes were in the gasket between the tbi and the manifold (on the firewall side) and then i found several more holes between the manifold and the engine.

 

Check your lower radiator to make sure it's not collapsing under high rpms. While under the hood rev the engine and look at the hose.

 

thanks good idea!

Because sitting at idle it doesn't overheat, and there is no spring/coil in that bottom hose. But it wasn't collapsing while sitting there at idle so I wasn't worried about putting one in. It may be collapsing hit high rpm/speeds.

I'll try it and post results

Thanks again.

 

Yea that lower hose has a habit of collapsing.

 

220* isn't overheating, although it shouldn't get that high on the highway with a good system and air dam.

 

yeah I know 220 isn't overheating just kinda high for freeway driving. Also sometimes it goes above that if I'm making a long drive. So I turn off the a/c and let it cool down a bit. Everything is in tack and air dam in good condition.

I checked out the hose yesterday and it didn't seem to be collapsing. I had a friend sit in the car in park and hold gas down about 1600 rpms for a while and I watched the hose. Temp was 200, but no collapsing. Someone told me you can't tell that way because the car is in Park and there isn't enough stress or suction on that bottom hose. Is that true?

I'm just going to replace the hose with coil/spiral inside of it and see if that works.

 

If that doesn't work, I'd take it to the shop and get a few checks done :

1, Pressure test for leaks and bad gaskets, and bad hoses.
2. Laser heat gun to check for hot spots
3. Vacuum re-fill to eliminate any air pockets.

This is assuming all the mechanicals that can affect the temp are OK, such as timing. (I had to do all three after replacing my heads, plus I made a custom alluminium air dam, plus I installed a manual switch.)

 

Also, install a lower temp fan switch if you haven't already.

 

ok guys,correct me if i am wrong please. Wouldn't putting a 160 t-stat in hurt your temp more then help it. I figure the t-stat just stays open so basically the coolant does not get a chance to cool down.If i remember correctly,the fan doesn't turn on til about 238 degrees.The last time i delt with a high temp problem it turned out to be the radiator cap..

 

i have a brand new stock replacement radiator..
new 16 psi rad cap, new 195 thermostat, new water pump, and a 50-50 water/prestone antifreeze mix..

i run about alittle under 220 on the highway thats about 40 to 55 miles an hour.. when i traffic it will go up to like 220 and then i put my passengers fan on untill i get moving again, at it stays at 220 for alittle bit and when i get started again goes back alittle under 220 and then turn off the fan.

i could get my temp down alittle more but i dont want to... i get great gas mileage now..

more water and less antifreeze with some water wetter and a 180 thermostat...

 

That's why you are supposed to change your PROM settings to turn the fan on at a lower temperature.

 

sounds good,maybe he needs to blow out the crud(leaves,dirt,etc )in the radiator fins,just un hook the top support mounts and you can actually pressure wash it ir take a air hose and blow out all the crap.alot of times i seen people have these overheating problems and it turns out to be that,Ya gotta figure even with the lower air dam in place it's kinda useless if the air does not get through the radiator

 

Hi. The overheating seems to be related to the A/C unit being on, and not to anything else if the car is completely OK with the A/C off.
This suggests that the refigerant is getting really hot in the condensor. That could happen if the A/C overpressure switch is not cutting out the compressor.
As the pressure gets higher, so does the temperature of the refigerant coming out of the compressor.
It sounds like you could try getting the A/C system pressure checked, to see what the output pressure is reaching.
That said, if the A/C is working properly it would suggest that your radiator is just on the limit of being able to cool the engine. The extra heat from the condensor just takes it over the top.
The coolant cannot go much above 220 at the pressures in a car's cooling system. This is because above boiling point the coolant absorbs heat as latent heat and starts to boil, instead of get hotter. So you could have a bigger problem with heat than is initially apparent.
Basically once the coolant tops out at around the boiling point, your engine is heading for trouble sooner or later.
I use pure antifreeze with no water. The heat transfer rate between the metal of the engine or radiator is mostly dependant on the coolant pressure and coolant boiling point, because the higher they both are, the less localized boiling can take place at the really hot parts of the engine. This is the invisible overheating that distorts heads and cylinders.

 

well its the same thing as when ur coolant temp is at say 220* ...the thermostat opened a long time ago, but all u gotta do is get some air flowing through and it'l cool down..

the thermostat itself slows down the coolant. unlike having no thermostat at all..

 

As stated before, I replaced the radiator with a new one. So I had a chance to clean all that stuff at the bottom radiator.

 

maybe I should give that some thought, it is only when the a/c is on when it's temps get high.

 

Ok, you're about to be corrected. A 160 t-stat will probably neither hurt, nor help. The "not getting a chance to cool down" doesn't have anything to do with the temp a tstat opens. If you look at heat exchanger formulas, they are based only on surface area of the radiator and the temperature difference between them and the atmosphere. All a lower temp t-stat will do is MAYBE take a little longer for it to get to max temp.

But a few things to check that can cause underhood temps to increase - is the ignition timing too retarded, or is the engine running really rich? I've seen headers on engines with retarded timing glow red hot. Also, fuel may be actually burning in the headers if the engine is too rich.

Oh, one other important and easy check - pull the radiator mount off and look between the A/C condenser and the radiator. Many times leaves and trash gets in there somehow and blocks airflow.

 

I just thought of a really simple possible reason for the problem.

Are your belts tight? When the A/C cuts in, it puts a real load on the pulley system.

If the belts are loose they will slow or even stop when the A/C is loaded up.

The water pump will then run too slow and the coolant will stop flowing and the engine will overheat.

 

Belt is tight