Cooling system question

[dave159]

When stuck in traffic for an extended length of time my temp gauge will rise above normal to around 200 degree mark and stay close to that until I begin moving at a normal speed. I have noticed that if I am running my AC the temp gauge will not rise at all (above normal) during extended idle time in traffic.

Does the AC system somehow cool the coolant? Maybe the temp gauge sensor is close to the ac system?

If it helps, I have a 94 Pontiac Grand Am w/ a 2.3L Quad 4 SOHC.

Just curious...

 

[N2OIL]

I believe your car has a relay to turn your electric fan on to keep air moving for proper heat exchange over your condensor.

 

[Matt_S]

When you turn on the AC, the radiator fans run continuously at a low speed to keep the condensor cool. This will also cool the radiator, leading to the behavior you're seeing. With the AC off, the radiator fans stay off until the engine reaches a preset temperature, then the fans are turned at high speed to bring the temp down, at which point they turn off. You'll normally see the overall temp a little higher, though, when sitting in traffic in this case. When you start moving again, the temp comes back down.

In short, what you're seeing is perfectly normal. The system is working as intended.

 

[dave159]

Okay, thanks.

 

[Cutehumor]

my girl's 96 Pontiac Sunfire 2.2 liter does the same exact thing. I thought maybe the fan wasn't coming on at idle. Could the relay be going out?
Also coolant is at full line, no leaks, antifreeze changed 16k miles ago, UOA showed no coolant contamination. My coolant gauge stays put in my 92 Mitsu when engine is warmed up. Flutuates in the Pontiac. is that normal?

[ August 24, 2004, 12:34 PM: Message edited by: Cutehumor ]

 

[Dan4510]

It also depends on the temp the systems is set to turn on the fan without the a/c running. Some systems are set as high as 230 degrees. If you want it cooler you might want to check out wiring in an accessory relay to turn the fan on earlier.

Dan