What is the normal engine temperature?

**noname** · 10-04-2009

Hello all,

I have a 2006 Base model Grand Prix. Stock 3800 series 3 motor.

The temperature runs just above quarter when on the expressways but quickly gets up to just over half when idling. The fan then kicks on and it drops back down only to go back up in a few mins.

Additionally when it is cold (first run of the day), as it warms up (expressway driving) the temp gauge slowly gets up to just below half then drops back to just above quarter. Is this normal? I have had it in to the mechanic twice now and he says everything is fine and there are no signs of head gasket or intake gasket.
I replaced the thermostat and nothing has changed.

Any input would be great. Thanks in advance.

**Pogo D Klown** · 10-04-2009

it's probably just warming up until the thermostat opens up, maybe it's sticking. should be fine though, as long as it isn't running hot

**Sabrewings** · 10-04-2009

Yeah, sounds like your thermostat is a little jumpy, but other than that it's operating as it should. As long as you don't get over to the red don't worry about it much. If you wanted to replace the thermostat, it can't hurt anything and is an easy job.

**noname** · 10-04-2009

I did replace the thermostat and nothing changed.
Do these temperatures seem normal?

Thanks for the replies.

**Sabrewings** · 10-04-2009

Yes. It seems like it's acting normally. What you described is what every car I've ever owned does.

**noname** · 10-04-2009

Lets hope so, I have had the car for a while now and never recall seeing temperature fluctuations like this.

I may have just overlooked it.

**BwolfGT** · 10-05-2009

Sounds normal to me, I wouldn't worry.

**BillBoost37** · 10-05-2009

Totally normal.

**airhead** · 10-05-2009

We've had 3 GTPs and one GT in the family and all of them run in about the same area you describe. My GTP will often get up towards the half way point in the Florida traffic but has never gone above that. They all run aroung the quarter mark.

**noname** · 10-05-2009

Well, I will continue to keep an eye on it.
Just seems odd it should be fluctuating and running so hot when it is only 40 - 50 degrease outside and a truck I drive gets up to 210 F and sits there all day.

Thanks for the input guys.

**Durk Diggler** · 10-05-2009

Mine did that too I'm glad I wasn't the only person that was bothered by seeing it fluctuate. I left my 190t-stat in and now with my pcm fan 2 comes on earlier so the temp doesn't rise and fall.

**Skeeve** · 10-06-2009

That is a good question though, what is considered "normal operating temp"?
my car sits around 195-210 on average, stock everything, new tstat.

**Sabrewings** · 10-08-2009

Originally Posted by Skeeve

That is a good question though, what is considered "normal operating temp"?
my car sits around 195-210 on average, stock everything, new tstat.

190-210 is where you get peak thermal efficiency in a gasoline engine. That's where it's designed to be.

**blueguy** · 10-08-2009

Unless your a high performance balls to the wall person and your NEEDS to stay cool...hence why there are 180*/160* T-Stat's for performance applications.

**Bio248** · 10-08-2009

anyone that runs a 160* thermostat in our cars is an idiot. i dont care how fast their car is or how well educated they are.

**Pogo D Klown** · 10-08-2009

I won't ever run one. Had a friend that did, car started running goofy. Stat wasn't working right. Cpl weeks later that car was on a flatbed on it's was to the junk yard. Didn't help that the guy was a complete TOOL either.

**reaper55** · 04-12-2010

Did anyone figure out the cause of this?? My 04 GP GT with the III seems to be doing the same thing but fluctuating from 1/2 about 201 degrees to 2/3 about 219 degrees (scanner).

I replaced my t-stat (OEM 195) and flushed the coolant no change.

once fan kicks in at about 215 temp goes back down...

Please help thanks

**CSteen85** · 04-12-2010

Actually, I"m having the opposite problem. I think my t-stat may be stuck open, because it's constantly running cold (below 1/4 mark), but it's brand new out of the box. I have to figure out how to change it myself - never done it.

I think it's sucking up my gas running that cold

**MrTube** · 04-12-2010

"Mine did that too I'm glad I wasn't the only person that was bothered by seeing it fluctuate. "

And this is sadly why many car companies now make the temp gauge an idiot light with a needle that never moves. I believe ford is well known for this.

I was actually surprised and happy to see the gauge in my 06 GP move after the car was warmed up

BTW, isn't there something in regards to fuel condensating on cylinder walls and washing oil off when using a colder than 195F stat? I thought i remember reading something about this and why most car companies switched to them.
And I would think a 160F would keep the ECM in open loop unless thats changed on newer vehicles?