A few months ago, I had the Grand Prix (2008, base, 122k miles) run hot, replaced the thermo and didn't have an issue until Tuesday, driving home and the temp stayed very low, just above the first bar. Did a few rudimentary tests Wednesday night and made the assumption that the thermo was stuck open rad hoses started warming up at about 140, OBD2 scanner. Tonight, I pulled the thermo and it was definitely stuck open (autozone thermo). Replaced with an ACDelco thermo and it is coming up to temp nice now, yay.
Drove around for a while, and here are my observations:
Temp outside was approximately 32 degrees.
First gradient on stock gauge is about 140 degrees
200 appears to be about 2/3 of the way between second and 3rd gradient.
While I was driving around, in traffic temps would rise to about 200-203 degrees
While driving on the interstate, temps where around 197 degrees
Would these be considered normal readings?
My Jeep TJ (4.0L) with a 195 thermo tends to run constantly about 210 degrees, maybe higher due to its wonderful aerodynamics.
John
