I have a basic question, but cannot find the answer for. What is the normal operating temperature for a 2003 monte carlo ss. I just bought the car and as soon as I signed the papers and drove about 20 miles the check engine light came on. The dealership determined the radiator fan was not working and replaced it. Now the car runs good, but the idle temp is close to 200. Is this normal.

 

i dont know about the 2003 but my 2000 had a stock 195 thermostat in it.

 

2002 SS manual says needle @ 210F or less is normal, and also going uphill/towing will fluctuate and approach the 250F mark - never did with me on uphill. When cruising, I always see needle on the 185F mark. Idle would go between my normal cruising mark up to lil hair past the halfway mark - I haven't idle long enough though.