2002 Chevy Cavalier Electric Radiator Fan Stuck On.

CCRUNNER2289

MEMBER
2002 CHEVROLET CAVALIER
4 CYL
FWD
AUTOMATIC
94,000 MILES

So I have 2002 Chevy Cavalier 2.2 L DOHV with just over 94,000 miles on it. I have been battling the cooling system for a while now and it seems that the thermostat is stuck open. I am unsure though because the engine heats up to its normal heating temperature of 195 it just takes longer then it used to. Also when I am driving on the highway the temp gauge will drop to about half of normal operating temp. Is a stuck open thermostat the most likely problem if I just put one in two months ago? Also just yesterday I noticed that my electric radiator fan was turning on all the time when I started the engine. What would cause that, a specific sensor or a relay switch?

Tuesday, March 24th, 2009 AT 6:46 PM

3 Replies

ZACKMAN

MECHANIC
4,202 POSTS

I really don't think that there is anything wrong with degrees. your thermostat. You need to fix your radiator problem first. You did say that the fan turns on all the time when the engine is on. Obviously, with the fan on, you will experience over-cooling, causing the engine to take longer time to get to optimum temperature of 195 degrees. And as the fan keeps the engine too cool, your gauge will show a temperature much lower than normal.

Check the relay for the fan. But I really think that it is your engine coolant temp sensor.

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Wednesday, March 25th, 2009 AT 12:15 AM

CCRUNNER2289

MEMBER
5 POSTS

Ok I wanted to first point out that the engine is single overhead valve not dual. Like that matters with this issue but it was bugging me. I switched out the engine coolant temp sensor and the fan is now off, however when I accelerate up to highway speeds (55mph+), the temp gauge still drops to about half of what it should be. I know you said it shouldn't be the thermostat stuck open but I really don't know what else could cause the temp to drop. Any other suggestions would be great.

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Wednesday, March 25th, 2009 AT 12:33 PM

ZACKMAN

MECHANIC
4,202 POSTS

I kinda figured that you have the 2.2L SOHC.

Then you will need to do one of the two steps. The cheapest will be to remove the thermostat from the engine, and perform a test on it. Just to make sure it is opening at the right temperature (195). The easiest way to do it is to boil the thermostat in water. Make sure that you have a thermometer handy and keep checking the water temp. The thermostat should start to open at about 190 and fully open at 195. Any other temp, the thermostat is faulty and should be replace, yes, again.

If the thermostat passes the test, then you need to perform other test. The instrument cluster. Unfortunately, you need to have access to a GM-approved scan tool to test the cluster. Here is the procedure.