Hi guys, Rabbit here.. Finally made a account because i ran into a problem and I have no idea what to do anymore. I have a 1988 Trans am with a 350 swap/rebuild Ive been having problems were she is overheating to the point were the coolant will start to boil and back up and be pushed out thru the overflow.. Currently I have Replaced Every Hose for the cooling system Put in a new waterpump Flushed the entire cooling system Put in a new thermostat So everything cooling wise is brand spanking new! However, No madder what she will overheat it will climb and climb until the coolant boils, Im stumped I fear I have a blown headgasket thanks for the help in advance!

Do you have the air skirt under your car ? make sure its there. Check your timing to.

Pull the radiator cap when it's cold, start the car, and allow for the air trapped in the system to vent. Watch the coolant carefully, and you will see tiny air bubbles. Once the bubbles stop (give it a few minutes), the air will be out, then put your radiator cap back on. If it continues, try the procedure again just to be sure. If it doesn't work, grasp the upper radiator hose with your hand when the engine is warm, and see if it's hot. If it isn't, you have no coolant flow, thus it won't be cooled. By the way, is it a new radiator cap, and if it is (or isn't), what does the pressure on the cap read....

Make sure you have a good radiator cap that holds pressure.
You should have at least a 16lb cap.
If you use a high flow thermostat some coolant will always flow. That makes it easier to burp the cooling system.
To me it almost sounds like you have low coolant (air bubble) or a bad cap.

I tried it 3 times but she still over heated.
It has coolant flow I can feel it going thru the lines


tdavolos- Yes I do , and the Timeing is set to 16 to run on premium fuel better

oil pan 4 - Cap is good and I the thermostat is a 160 Degree


So I am sure their is no air in the system.

ever check the radiator itself? flushing isnt a cure all unfortunately i had my system flushed and my fluid looked like crap after they filled it, its possible that its just shot. I just had to replace my radiator and the system runs like 15* cooler, internal blcokage is hard to find but it could be that

Also have you checked fan operation?

If youre worried about a blown head gasket; Check your oil and antifreeze make sure none of its mixing into that wonerful milkshake substance lol Just to knock out any fears in the back of your mind go get a compression tester and test all the cylinders, if you find 2 adjacent cylinders that have a close reading and theyre lower than the other 6 cylinders then you blew a gasket

Hopefully thats not the case

If your getting coolant flow, w/no trapped air, and your fan is working, and your running a fourteen to sixteen pound radiator cap that is functional, there is no reason why your coolant shouldn't be cooled. Except for.....;

Please tell me that your not talking about your base timing here....

Sorry the firebird is timed to 14 the 5.0gt is timed to 16, I gotta little confused while posting

When you had the cap off with the engine running did you notice bubbles continuing after the car warmed up? You are leaving it off until the thermostat opens?

14 degrees is a lot. When you set it did you have the flat 4-pin connector unhooked. Try backing down to half that.

I usually replace the radiator last. But that always seems to be the problem.