Cooling Issues. Ok so i have some weird sh*t going on any ideas? I drive a 95 lt1 car. It curretny has about 148,000 miles on it and it runs like a raped ape. The entire ignition system was replaced last feb. and the waterpump, radiator, and cooling fans were replaced shortly after. This past summer i had issues with overheating due to cooling fans not coming on. So i replaced the ect. This still didnt solve my issue and due to lack of time to trouble shoot I wired the fans manually with a toggle and removed the thermostat. Problem solved for months. I installed a 160 degree thermostat about a month ago and havent had any issues until now. My temp gauge keeps spiking and if i get out and crack the bleeder screw loose it will drop almost instantly. I 've bleed this system numerous times in the past with no problems, and have tired over and over again since the problem started, but it keeps doing this every couple of days... What the heck is going on? Is my gauge lying? What could be causing my fans issue? Im ready to just intall a autometer to be sure... any input would be great. Thanks

 

For the fans you could try this test procedure & see if anything comes up.
https://camaroforums.com/forum/93-02-general-41/quick-test-engine-fans-54192/
If you bled the cooling system properly and it keeps getting air, on the best case it could be due to a bad radiator cap or an empty or leaky overflow canister or connecting hose. ( When the engine cools it sucks coolant back in from the overflow canister, if there is no or low water or a leak in the overflow system it is going to suck in air instead).
On a worst case, combustion gases are being pushed into the cooling system, which could be due to bad head gaskets or cracked or warped heads, cracked block, etc.

 

Ok, I totally understand that there is the somehow air entering the system. Either from a defective overflow, radiator cap, or some other craked or busted hose. I guess that there is a slight chance that one head gasket could be letting air blow air where it shouldn't, but it doesnt seem likley to me. The car runs very well, and shows no other signs. The real thing that bothers me is how can a temp gauge shoot well over normal operating range and then drop lower then 180 in the matter of seconds and yet still be operating correctly? I dont see how engine temp can change that quickly. Just so you know it has also been well into the 20's here when its doing this. Seems like a screw balled gauge reading to me. Something isnt right thats for sure. Thanks for the reply pete.

 

You can verify if the temp gage is working properly by using a test gage or a scanner. There is a possibility that the new t'stat want bad, and may want to try a different one. For peace of mind, get a test kit to check for combustion gases in the coolant, also check the water pump for leaks. Some leaks only appear when the engine is running and some others appear after the engine has been stopped for a while. Good hunting.

 

I am going top start with pressure and dye testing. What is the correct pressure for the radiator cap so i can be sure that i get the right one.

 

The correct relief pressure is 18psi.