Hi, I drive a buick 1997 park avenue base. Has alil over 200k miles, automatic. On the road going higher speed like highways, normal temp is about 183, but when I stop at light, Or idle for alil while, the temperature increases right about 210, then the fans kick in, then goes down to about 200, it goes back and forth 210 to 200. I know that the engine should stay at the same temperture more or less. So I know something wrong. I believe my fans arent turning when it's suppose to, to keep the temp balanced.
Frankly your old GM 3.8 engine seems to be running in the correct temperature range.
The PCM should command the fans to come on at low speed at around 210° (+or- a couple of degrees).
Yours are.
The PCM should command the fans to turn off at around 201° (+or- a couple of degrees).
Yours does that too.
The thermostat that can be used in those old 3.8's ranges from 180° to 195°.
Yours seems to have a 180° thermostat installed in it since it maintains 183° while driving.
That uses the old GM 3 relay fan setup. Here's the wiring diagram but like I say, it's working as designed so I wouldn't look for trouble where there isn't any.
Well it could be check the fans. Also watch my video how to fix an overheating car Scotty. It's on YouTube and it'll tell you anything it could possibly be
