I just picked up a '88 Trans Am GTA. It has the 5.7L 350 TPI engine. Please excuse any of my ignorance as I don't have real good knowledge of this particular car/engine yet.

Basically what is happening is this:

The car seems to remain about 195-200 degrees while highway driving. Not a problem. In town, stop and go, it will rise above 235. I haven't been stuck long enough to see if it goes higher. I am fairly certain that it the fan does not run. When I stop I find the coolant overflow reservoir full. The coolant will almost always steaming and bubbling out of the overflow reservoir cap which for some reason has a hole in it(looks like it is made like this for some reason). The oil dipstick looks clean from what I can tell.

It would need constant coolant refilling if I were driving it regularly.

I do need to check the air-dam. I believe it is all there but it looks pretty beat up. Is there anywhere on the net I could find a picture of what the assembly is supposed to look like?

I am thinking of replacing the thermostat, radiator cap, and coolant sensor first. Is there a fan switch also? What should I look for or replace first?

I don't know what the coolant mix is since I've only had the car 3 days but after I drain the radiator and check it I will replace with a 50/50 mix.

Well, anyway..... If anyone can point me in the right direction I would really appreciate it.

 

try replacing your thermostat, then look into your fan switch they should be kicing on maybe just a loose wire--if you have good luck

 

I am definitely going to replace those items. I am just concerned that I might have compression getting into the cooling system which would lead me to believe I have some head gasket problems.

Is there anything else I should look for or check out?

 

normal op temp is around 200 to 220, stock thermo is 195 fan doesnt come on until around 235. The TPI has two temp sensors, one in the front of the motor for the computer, this controls the fan, and one in the head for the temp guage.

If you arent sure if your fan is coming on, switch your a/c on and the fan should turn on. if you have dual fans, only one comes on with the a/c. If the fan doesnt come on check the relay.

Having a good rad cap is important, I think the stock cap is 16# and making sure there is no air trapped in the system is also important.

 

Sounds like the car is running the right temprature but you have a preasure leak. Its more than likely the cap, but I would still preasure check the whole system. The cap should hold 15psi, if it leaks replace it. For every 1psi you gain 3 degrees on the boiling point. 50/50 water antifreeze boils around 218 F, but add 15 psi and you now have a boiling point of 263 F.

 

I pulled the cap and checked it out some more last night. It seemed as though I have a good flow. I could see the coolant pouring back into the radiator. I assume the water pump is functioning properly. Upon closer inspection of the radiator I found that there is a small amount of wetness/smoke coming from the plastic reservoir on the cap side. I think there are some very small cracks. The hoses seem fine. No leaks from the water pump or hoses. The radiator also is very gunked in the front on the cap side. The heater core seems to be in good shape. No leaks and it pours out some serious heat when the car warms up.

As the engine began to heat up the level in my radiator rose until it started pouring into the overflow hose. At this point my temp gauge was reading about 140-150 degrees. I wasn't able to get it up to 195-200 with the cap off because I didn't want a mess.

I am going to replace the radiator, cap, radiator fan switch, thermostat, thermostat gasket, and coolant sensor very soon. Hopefully this will be all it needs. I'll keep my fingers crossed.

If it still has a problem I guess it's the pressure check and then the complete engine rebuild. If I'm gonna pull the heads I might as well buy a new short block and rebuild the whole thing. The tranny and rear are newly rebuilt.