Driving my car all day today and i decided to take it through an express drive thru car wash over at Chevron gas station. Pull up to where you punch in the code for your wash and my car proceeds to enter the wash. All of maybe 2mins my car quickly goes from cool to past the halfway mark on the engine temp gauge and it was creeping up to the "over-heat" zone. The wash was over when i noticed and i quickly turn the heat on full blast and roll down the windows. I get the car moving down the road to get some air flow through the engine and it slowly but surely returned back to normal engine temperatures. I got home, checked my coolant and everything seems normal. Ive taken my car through car washes many times before and i have never had this problem.

 

Sounds like the cooling fan didn't come on. I'd start by checking fuse. If everything looks good, I'd start the car, and turn the A/C on to max cool. If the fan runs, double check to make sure the fan is running full speed. Also, check the radiator, is it partially blocked with debris? If everything still looks good at this point, I'd go back and try to recreate the original failure (warm, parked, idling). If your problem persists, I'd be suspicious of the Engine Coolant Temp Sensor (ECTS). Should you decide to change it out, change the plastic electrical connector too. Use OEM parts (GM dealer will have them). Total cost about $45usd. Good luck ....

 

Actually now that you mention it, i dont think i remember hearing the fan running. It might have been my imagination or maybe it was running and i just didnt noticed. Ill check to see if there are indeed any blown fuses for the fan. Hopefully i can get this problem solved before spring. I live in vegas and it get blistering hot during the spring and summer. The last thing i need is a blown radiator or a over heated engine while sitting in traffic

 

If it's not the cooling fan fuse or relay or even the motor itself, it may be your thermostat. Perhaps it's time for a new one.

 

Checking to see if the fan is running should be as simple as looking at it when it should run.
There are two times it "should" run
1. When the A/C is requested to be operating.
2. When the heat gauge says it is hot enough to do so.

Of course checking for fuses and such is certainly a good idea but however it seems to me it would be better to first verify it is not running when it is supposed to.