So my Firebird'* having an overheating/pressure in coolant system problem. I joined a Third Gen F body forum but they're really not that helpful. I feel like they keep my diagnosing going in a circle and I always end up back where I was before. You guys have always been extremely knowledgeable with Bonne stuff and thought maybe some of you guys might be of some help with the Firebird as it isn't a Firebird only problem, it'* a coolant system problem.

You can read all of the posts that I've made and the responses to them at this link:
http://www.thirdgen.org/techboard/te...=1#post3819118

From what I read, they are on the money with their suggestions.

First you need a scanner to know what temps and parameters are in place.
You need to check the fan circuit as to why they aren't running.
Compression check the cylinders. This will confirm or deny a head crack or gasket leak.
Check the size of the radiator, is it undersized for the application?

To be totally honest they aren't running you in circles, you are doing that to yourself by not checking the things they've suggested. I'm speaking from my own experience and running in circles myself.

The radiator is fine, I've checked that. The fan will be hard wired to a switch in the next couple days. I just need good weather to do it. The fan circuit could be messed up as I didn't do the engine swap but it that and the electronic connections seem to be done not too great.

I really don't think I have a head gasket problem. This is the problem though. I can't do a compression check untill I can drive the car to work to do it. And I can't drive it while it'* overheating.

I have checked everything suggested except for the compression test because I can't do that yet.

Can't you borrow the compression tester for an evening?

No I can't borrow the compression tester. What a tech was going to let me borrow is something your put over the radiator with the cap open and tests if the head gasket is blown by testing for exhaust in the coolant. Problem is, he has the tester and is out of the fluid for it and we missed the Snap On guy today.

He'* gonna do a coolant pressure test. Hows your t-stat? Maybe throw a new one in for kicks and see if it overheats still. Hows the condition of your coolant? Maybe do a flush, old coolant wont cool nearly as well as new coolant. Is your water pump operating? You should be able to see it flowing with your rad cap off when the t-stat is open. If it gets up to temp and you dont see any coolant flowing in the radiator then its a good bet your water pump could need replacing.

For testing purposes I've just been running water in there. I've flushed the system numerous times. Everything is flowing. Again tonight I ran the car with the radiator cap open and I saw the water flowing fine. I felt the hose coming from the thermostat to the radiator and it was cool while the other hoses were warming and then the thermostat opened and the hose did get hot.


Here'* the interesting thing I did tonight that I never did before. A friend had his 88 Camaro with a 305 in it over tonight and it does run on the warmer side. His car has a temp guage and my car doesn't, but his car was running at 225* when driving. Only difference between our engines is that mines carb'd and his is fuel injected and some hose placements and pully order.


Anyways...I had the cap open while the car was running and had a digital thermometer in the opening. The temperature light by the guages went on when the thermometer said about 195* and then at about 205* started spewing water out of the radiator cap hole. I have no difference if the water at the top of the radiator where the cap is would be cooler than the coolant in the engine or not. Maybe the coolant in the engine is 225*???

GM temperature gauges are whack and should be for reference of an out of the ordinary rise or fall,(Mine reads a consistent 200 with a 180 degree thermostat.) You said when the water came up out of the fill hole @ 205, I am assuming thats just after the thermostat opened and caused it. The temperture of the water in the block would be the same as coming out the fill hole at that time. the water travels such a short distance in that timeframe it couldnt be cooiling enough to detect.

Thats the exact opposite of what a guy on the F Body Forum said, lol. I've got a 180* Failsafe in the Bird. Unfortunatly no guage at all though, thats why I tested the temp at the radiator.

So that pressure is normal from what you're saying?

I dropped the car off at a shop down the road today. I know I'll be paying more than if I had a tech at work look at it but I can't drive it the 10 miles to work unfortunatly. I did get the fan wired up to a switch today too. Hopefully that helps some.

If the engine does present any other issues and doesnt overheat enough to flood the reservoir or throw steam, I wouldnt worry about it. I had a two 2.8'*. 1 in a 85 Camaro and 1 in 85 *-10. Both ran over 200. The truck as I remember sat at around 210. Not a fan of the engines, but they each took a beating.