my 2002 monte ss 3800 have been over heating a lot lately , i tightn all the hose clips , replace the radiator 3 days ago , the thermostat was replace about three months ago for some reason the temp is still high when driving with out the a/c on, but when the a/c is turned on it doesnt over heat at all the temp goes down , i check the fans they do work properly , so do you guys think i should change the thermostat from 195f to a 180f would it help or do any of you know what might be going on under that hood..... PLEASE HELP ME RESOLVE THIS MATTER BEFORE IT GETS WORST .

 

I would flush out the system real good it almost sounds like to me like you have a plug some where in the system dex cool is known to gunk up pretty easy

 

How hot is it getting?

What was replaced and why?

Age of the car? Etc.

 

I have never validated this, but I heard turning on the AC in a GM car will activate the radiator fans. If that's true, it explains that observation about the temp.

My concern is, it's an '02. Has the coolant ever been flushed? Regardless of DexCool or the traditional "green stuff", anti-freeze has a chemical composition that does break down over time (therefore, it will not hold all it's normal properties for temp control and can begin to gel/sludge up and create a clog).

First thought, perform a full flush. If you are doing it yourself, get one of those bottles of Prestone coolant flush to run through it.

Also, how bad is it overheating? What temp is it reaching?

 

One Fan kicks on at 212°, the other fan kicks on with the A/C was my understanding.

 

ok im going to flush out the whole system , im going to have done professionally to make sure its done right....

 

it gets a little overheat than when the fans kicks on it would go back down, but when i squeeze on the hose it has a lot of pressure kind of like a rock solid , the thermostat was replace three months ago , the radiator just got replace three days ago ,because the mechanic i go to sais my radiator was bad, but now it turns out it wasnt even the radiator that was bad after all because the pressure on the hose's are still high and some time the coolant would leak out from both ends of the hoses thats connect to the radiator .

 

the mechanic i go to were suppose to flush it out during my tune up three months ago in the car , but now i'm thinking maybe he didn't fully do it right, he is a good mechanic but people always makes mistakes, and the over heating usually passes the middle a little than the fan would kick on and the temp would go back down, it usually goes up when the car stop at a red light and when you start driving again the temp slowly goes down to normal again.

 

Was the thermostat put in upside down??

 

The 12 o'clock hashmark on your temp gauge is 210*. Your thermostat opens at 195*, and your fans kick in at 212*. The temp gauge going just past the middle when the car is stopped should be normal.