99 Grand Am GT Unstable Temps, I have done the following

1. Upper radiator hose replacement, (hole) a month ago

still unstable temps

Friday
2. Had sludge ridden dexcool removed, flushed entire everything. Replaced with green stuff . by mechanic
3. Mechanic also replaced the thermostat(he told me its a 195 degree thermostat)
still unstable
Before all this, it seems the temp of the car was always around 200. Then it started to fluctuate, never getting to red though.

Now the lowest operating temp is about 205 and thats with the air conditioner on because both fans are running ( i saw them working)

But with the air conditioner off, the temp gets to constant 210-215 and even a little higher if sitting at stop light or in traffic. So im afraid to not have the air conditioner on because I dont think the car should have a temp this high on a consistent basis.

Am I missing something? Is the relay not working? Or what is normal temp for my car without doing damage. Its driving me a little crazy because its not acting the way it used to temp wise.

Thanks

PS. it was acting up with the dexcool too. I was just hoping the change out would help things but it didnt.

Some likely gremlins could be a bad flow of coolant through radiator, even after flush some tubes will stay pluged in a an old radiator. Some scale/rust blocking passages in engine block or a leaking gasket near exhaust valves can transfer a lot of heat to your coolant. It seems like you covered the normal stuff as best you can. Good luck.

i would do a pressure test. sounds like you may have either a bad LIM or a bad headgasket. fairly common on the 3400's

i would do a pressure test. sounds like you may have either a bad LIM or a bad headgasket. fairly common on the 3400's


If i had a bad headgasket, would I always see the coolant mixed in with the oil or is that only in the later stages

If i had a bad headgasket, would I always see the coolant mixed in with the oil or is that only in the later stages

not always, it could be an external leaking headgasket. really depends on where the gasket is blown

how many miles are on your GA, and have you changed the LIM on it yet?

thanks, i will get the pressure test.

120,000 miles on the car and I have not replaced any lim or headgaskets yet.

120,000 miles on the car and I have not replaced any lim or headgaskets yet.

with 120K on the car, and the LIM (lower intake manifold gasket) not being changed...i would suspect that since they are so common on almost all GM motors. its not a matter of *if* it will go bad, it is WHEN. obviously if you get a pressure test and it ends up being the headgasket...you will change the LIM since you have to tear the plenum off to get to the head gasket.

anything else i should do while they are in there? or a certain type of part I should tell them to get? It seems that I always learn stuff to do after the fact and have to keep going back.

Is there more than one type of headgasket and lim gasket part to choose from?

thanks for you help by the way