2001 Monte Carlo 3.4L
108K miles

Ok. My car has been running hot for a while and I cant figure out why. Twmp guage has never got to red but pretty close a few times. Within the past year ive changed the water pump, temp sensor twice, thermostat twice, intake manifold and plenum gaskets, and flushed/bled the system everytime. The fans work so i didnt change those, but i did change the fan relays and fuses. There are no visable leaks anywhere but it continues to run hot. Itll run fine for about an hour, then the temp guage will go to 3/4 and car begans to run like crap. Any ideas??

Oh ya. Even though the fans work, they are really loud, sounds like the bearinf in the fan motor is dry. Could this cause the fans to not spin fast enough and engine heat up?

 

Sounds like you have blown enough parts on the motor, The cooling fans come on about 225-230 degrees. Are both fans coming on when it gets to temp ? Does the AC fan come on when you turn on the AC ?. Can try using a pressure tester on the system and see if it builds pressure when it gets hot . But sounds like it could be that fan your referring to being loud.

 

Does it only get hot when idling (traffic or stops)? If so after changing all of those parts I agree with Jeffs02rwdSS that it is the fan that is making noise. Do both fans cut on when you use the max A/C, they should. Check that too. If it is overheating all of the time then look at your radiator and inspect for leaks or even better do a pressure test as stated above.

 

The AC fan does come on with AC. Im not sure if it comes on any other time. Ill check that today. The other fan cuts on and off like it should and keeps temp out of the red but it doesnt come on with the AC. It also doesnt seem to stay on as long as it should. Itll come on for like 3 or 4 secons and go off for 10 seconds back n forth. The AC fan is A LOT quieter that the other fan as well. Lol.
It does get hot mostly when idling or in stop n go traffic. If im on the freeway temp guage might get a little past halfway but overall it seems fine.
Ill check the fans again today and try to get a better idea of when each fan turns on and off, and the consistency of each and post the results. Thanks for advice guys.

 

I have a similar issue with my 06 Pontiac torrent, also has the 3400 motor.
Changed out the upper and lower manifold Gaskets and that helped for a little while.
So took it back to the Garage and they flushed the system and then it was good for a little while.
Seems like it needs coolant but I am not loosing it.
I know what you mean about the loud fans.
Once in a while you can't get thru the drive thru on idle. Pretty strange situation.

 

Ill be damned.... I decided to completely flush out the dex cool and put conventional green antifreeze. Runs great now. I did this about 3 days ago and it hasnt overheated since. Temp guage hasnt even hit the halfway mark.
Ive always heard of people switching from dex cool to green but i never expected it to make such a difference.

 

And this is probably just a coincidence, but the fans sound normal now and seem to be working correctly. Im not sure how the hell that happened. Lol

 

Congratulations. Now, start shopping for a new radiator.

 

You're not suppose to run conventional green in your car. Period.

 

Thus my comment above. Since I started running Dex in 1993, I do lose a lot more fluid than I ever did with green, but I have also never had so much as droplets come out of my radiators. Given the choice between buying Prestone and buying radiators, for me it's an easy choice.