I have a 2001 Pontiac Sunfire 2.2L.

I had the engine replaced a few years back. Not sure what came stock on the car other than it was a 2.2L.

I have the Haynes manual for the car, and it seems there is a 2.2L OHC and 2.2L OHV. The main difference I can tell is that one has coil packs. The engine I have in there now appears to be a 2.2L OHV due to the presence of the coil packs. I was having issues with overheating, and found the cooling fan motor to be dead, so I replaced that. It's now working, but still had overheating problems so someone suggested it may be the thermostat, so I went down to AutoZone and picked up a new thermostat (the original had 200k+ miles on it). The one I pulled out had 180 stamped on the end of it (assume that was 180deg) and the new one was 180deg as well.

Well, after installing the new thermostat, it appears that the engine is running on the cool side now and my heat doesn't work as well. Seems like it averages about 150-160deg when the engine is warm, but if I stop and just let it idle, it will creep up to near 195, but not enough to turn the fan on.

In looking at the Haynes manual, seems the 2.2L OHV thermostat is supposed to be 195deg. Is it possible I originally had an OHC engine and they replaced with an OHV engine and just used the original thermostat?

Could that be the reason I seem to be running cool? Or am I not really running all that cool?

What temp range should I see when the car is warmed up and running?

PS: Wouldn't supprise me if they didn't screw this up... After about 2 years, when I went to change the plugs and wires, found they had the #1 & #4 wires switched (1 to 1, 2 to 2, 3 to 3, 4 to 4).

Also, am I going to run into any problem with the engine running slightly cooler (if it really is)?

had same problems, reinstalled thermostat and water pump, got air pockets out also

or the thermostat could be rated for the wrong temperature. it does happen