Thread: Running Warm - rad fans never go on high?

Morning all, new member here, just signed up.

I picked up an '04 Grandprix a few months ago and I've been trying to figure out the cooling system in the car ever since.

First off, how hot do these engines run? My needle will range between the 3 and 4th tick if i'm stopped long enough in traffic. Seems very warm to me. Forgot to mention - the fans will go on low speed by themselves, but it's not enough to really cool the thing down. With the AC on and the engine running warm I've noticed the fans will hit speed on occasion.

This is what I've done so far:
Checked coolant PH - Ok
Replaced Thermostat
Replaced Temp Sensor.

I was going to replace the relay, but then found 3 of them in the car, that stumped me, so i did a little more reading and found if you unplug the temp sensor the fans should go on high as a fail-safe. I tried that and sure enough, the fans go on high. Thats when I decided to replace the temp sensor instead of the relay(s).

My solution during the warm weather has been to unplug the temp sensor and let the fans run on high, but I'm afraid of burning something out doing that.

Any ideas would be appreciated!
thanks all.

Your sender for the temp gauge may not be reading properly. Or its possible you might have air in the cooling system.You should try to bleed out the cooling sstem and see if that stops the issue.

Bio - I guess I'd have to get a temp gun or something? Unless your gauge is different than mine, the gauge is divided into to 5 sections, by tick marks.

Sic6 - I bled the system after replacing the temp sensor, I guess it's possible the gauge is reading the wrong temp, but it seems to stay where it should while driving, and I would think the relays should intercept the temp signal and tell the fans what to do prior to the signal getting to the gauge?

Hourang - Yes the fans have gone on HI if the AC is on.

I'm stumped.

well, like I said, the AC doesn't *always* put the fans on high, even if it's running warm. I could certainly try running the AC and give it a try when it's running hot.

Not quite sure what you mean by a scan guage? Could you be more specific as to waht I would search for?

First off, am I right in assuming the needle should stay relatively stable between the 2nd and 3rd part of the guage once the engine has warmed up?

Thanks all

The gauge will go above the 3rd tick on a hot day. The fans do not kick on until 210-220F. I drive an 06 and noticed the same thing. A 95 Lumina we had ran about the same.

I run my A\C a lot which runs the fans on low so my temp doesn't usually cross the 3rd tick. however If I turn the A\C off and sit for some time, it will.

Essentially it hangs where the gauge in this picture is. It will climb slightly above the 3rd "longest line" before the fans kick on with A\C off. It never goes near the red shaded area. When cruising it hangs near center of the gauge due to good flow through the rad.

MrTube, thanks for the clarification! My guage hovers right around that tick as well, so I guess that's normal. But I've noticed that when I get home after driving for a while, I can smell what seems like hot coolant. I don't know if that's new (recently got a coolant flush) or if I just never noticed it before. Anyone else notice that smell when the car is warm?

Haha, thanks. I'm obviously new here.

Originally Posted by Scottydoggs

that guy aint logged on in 3 years and this is a 6 year old thread now.........start your own thread with your own issues.

But here I am!

But I've been driving a Chevy Sonic since 2012. Sometimes I miss my GP.

Personally, I see no reason to start a new thread. This one still contains the same useful information,

Back from the beyond! Have seen many great things in 6 years. . Glad to see my thread has helped some along the way. Cheers.