pianiy

iTrader: (2)

91 Firebird L03 Auto... just replaced the EGR valve, EGR solenoid and MAT sensor to get it to pass emissions. Was throwing a code 32 before the valve was replaced but NO codes now. The plugs have also just been replaced with Rapidfires.

Thats just the latest work I've done to the engine but this is the problem. At least once every time I drive the car the temp guage climbs up to almost the red area but then it drops rather quickly back to about 200 or so. The thermostat is only about a month old, replaced stock for stock 195*. It seems that if I give it about 3/4 throttle when its reached this high temp it causes it to drop back down and it'll stay in the normal temp operating range for most of the time. I believe the fan is working fine but it doesn't really matter as the car is moving (most of the time at highway speeds) with air constantly flowing through the rad. The air dam is there and functioning. There are NO other mods than what is listed in my sig.

Could my CTS be faulty? I looked at a couple other threads, one being in the tech section about a guy replacing the sensor on the passenger side head under the exhaust manifold. If I only knew what to replace this wouldn't be so difficult.

Z288Iroc

Mine does the same thing, at the same point I drive to work everyday it shoots up to 240 then within 10 seconds it drops back down to 180.

FLYNLOW92rs

iTrader: (53)

I had that exact same problem also, until today i went out and took out the thermostat.

All i did was push it in and out for a little bit, and basically move the spring for about 10 minutes, I put it back in and it stopped doing that.

Try that, It fixed the problem for me.

pianiy

iTrader: (2)

Yeah, it seems to be acting somewhat like a stuck thermostat but its only a MONTH old?!? Garbage parts.

pianiy

iTrader: (2)

Just replaced the t-stat with another stock 195* unit and the gauge still says the engine gets up to 240*. I'm gonna have to check the service manual on this one to see if the coolant temp sensor is working right... just haven't had the time yet. Still open for suggestions...

pianiy

iTrader: (2)

It seems I may have fixed the problem. Yesterday the temp gauge stopped dropping back down to normal and instead redlined itself. The engine sounded ok, not the usual knocking you get when it overheats but I pulled over anyway. The reservoir tank was almost full but nothing was bubbling or boiling out. I took a rag out of the car and put it over the radiator cap and turned it only about 15*, just enough to break the seal and let air into it. For some reason, this cause all the air in the system to bubble out into the tank. Once it stopped bubbling, I turned the ignition to on, engine off and let the fan start cooling the radiator down, this started to draw the coolant back into it from the reservoir tank. I didn't have any water on me so I couldn't top the tank off to the fill line but I repeated this whole process once I got home.

Since then, the guage has been back to acting normal but I think I have a coolant leak somewhere near my heater core. Its not enough to make it drip but I turned the car off yesterday evening and it was steaming from that area. I have to check into it later on.

SO, it could have been air in the system causing my temp guage to act up. I know I didn't have enough coolant in the reservoir tank to fill it to at least the cold fill line so it was probably drawing air into the system.