Engine temperature fluctuation idle vs. drive

cavalier
engines
overheating
chevrolet
gauges
airconditioning

#1

Hi,



I have a 2002 Chevy Cavalier 2.4L 4 cylinder with 105K miles. The engine temp gauge rises above normal (~220 degrees) when idling/in stop and go in traffic, but when cruising it drops to normal (~195 degrees). This may be related to the activity of the AC, which only produces cool air when moving, and only then at fast fan rates. At low fan, or when idling in traffic, the AC blows warm air. I recently (~ 1 year ago) had my water pump replaced and the coolant system was flushed at that time. The car has been well maintained and I’m the only owner. Any suggestions would be greatly appreciated!!


#2

Are the radiator fan(s) coming on when they should? What is the thermostat temperature? Are you loosing any coolant?


#3

Haven’t checked the fans - when are they supposed to come on? I haven’t noticed any coolant leaking from the car. I’m going to check the level tonight and top it off if needed. The only temperature reading I’m getting is from the gauge in the car - it’s reading 195 when driving but creeping up to 220 when idling. Is there another place I should check for the temperature? Sorry if my questions are simple - I’m relatively new to car repairs. Thanks for the help!


#4

What you describe is almost certainly a cooling fan problem - as in the fan not operating. The fan should be on any time the A/C is on. It should also kick on automatically when the coolant temp reaches something in the 220-240 range.

To clarify - when you say the temp gauge rises above “normal” do you just mean past where it used to be? In any case, it sounds like your fan is dead - jump 12V directly to it first to find out if its the fan motor. If the motor runs then start checking fuses/relays/wiring.


#5

Thanks for the info! Yes, by normal I’m referring to where the temperature used to be. I’ll give this a try. Thanks so much for your helpful discussion!