Overheating problem

**thuisman** · 05-21-2015

Hey guys! Just joined. I have a 2002
Grand Prix SE with the 3.1v6.

I've had a slight overheating problem for awhile now. First of all, my gauge is not correct it says it's running cold (about a 1/4" from 210 mark") even though it's warmed up, when I hook up my scan tool to it and go to live data, it says it's running at 210 or so.

The main problem is that when I'm at idle for 5-10 minutes, the gauge will slowly start to climb, the gauge says 210 but my live data will usually be around 220-226 degrees. I don't hear the fan running when it's gets that hot UNLESS I turn the A/C on. So when I turn the A/c on, I can hear the fan running at high speed, and it will go down my car to normal temperature, if I have time, I'll take pictures of it later.

That's all I can think of right now. Any help will be appreciated and ask if you need more detail in a certain part.

Thanks!!
-Trevor

**Fivefingerdeathpunch** · 05-21-2015

Coolant flush and a new thermostat is where I would start.

Possible that the thermostat is not working 100% correctly and causing the temps to rise that high.

**Scottydoggs** · 05-21-2015

id try a new temp sensor. if the 3100 works like the 3800 temp sensor its got 2 parts, one side to the dash, the other to the pcm. the dash side may be the one that controls the fans too.

if you unplug the temp sensor both fans should turn on full time for ya till you get it sorted out.

**J57ltr** · 05-21-2015

3.1? Are you sure you aren't losing coolant from the LIM those things are notorious I did 5 different cars all had coolant leaking and pooling on the manifold and at the sides where the LIM meets the head. you could have air in the system if it's leaking.

Jeff

**thuisman** · 05-21-2015

Thanks for the reply!!

Where is the temperature sensor located? I was thinking that too

**thuisman** · 05-21-2015

I don't think it's that, I don't see coolant leaking anywhere and i don't notice any coolant loss. But I'll be sure to look into that after I change the coolant temp sensor to make it so the fans work properly

**Scottydoggs** · 05-21-2015

should be under the t stat in the lim. im not real familiar with the 3100. but thats where they seem to be in most cars these days.

**thuisman** · 05-22-2015

I changed the coolant temp sensor, and now it's opposite, the gauge says I'm running just under 260 degrees but my scan tool says it's running at about 190-200 degrees. Is there a way to put pictures on here?

**Scottydoggs** · 05-22-2015

use a image hosting site, copy the url and paste it in the pic icon in the reply box.

try another temp sensor, those things are a nightmare. known to be bad brand new. if you can get a delco go with that brand.