When I was on the way home frm picking up my recently purchased 2001 Monte Carlo SS it began to overheat. This was after driving it, mainly on the highway, for about 30 minutes. The car really began to overheat while I was stopped in traffic. After pulling over and letting it sit for about 15 minutes and filling it with engine coolant the temp. gauge went down. I would like to note tht NONE of the fans went on. After driving again for approx. another 30 minutes (and thankfully into my driveway) the temp. gauge had begun to go up again. In turn, I purchased and installed radiaitor/coolant fan relays. Tht's as far as I got. I'm waiting once again, for the engine to cool down b4 I take it for a test drive. Any input regarding and possible solutions will be much appreciated.
Another note: No check engine light. I also had used the code sensor and no codes are coming up.

 

Are you loosing coolant?
That really is sad, you just bought a car and its giving you trouble after its been recently purchased. FKN dealerships!!!!!

 

Sounds like you are losing coolant. Check for the obvious leaks like drips and what not. My monte would lose coolant slowly, which ended up being LIM gasket.

 

you could have checked your relay by putting it in the fuel pump one or another slot and seeing if it still works. instead of going to buy another one

 

The car, which was bought privately, had been sitting for some time. Honestly I didn't chk the coolant level. At this point I have filled the cooland resioviar. After replacing the two 4 prong relays for fan 1 &3 (The middle 5 prong one was not available at the parts store & all local parts stores were closing) I drove it around for about an hour an a half. The temp. guage was fine (getting a little warmer when in stop & go traffic and cooler on the highway as to be expected). It was not until I pulled into my driveway tht the temp guage went a little more than quarter past the mid-way mark. It did not go into the red. This morning I will chck the coolant & fill if needed. Unfortunatly I have to go to work, b/c the last time I chcked this **** is going to cost money. The ride there will be fine b/c it's a short drive.
So after changing the third 5 prong relay, then the thermostat maybe tht will be all tht is needed. In nthe process of doing tht I will chk for leaks. If there is one its def. not internal (oil is clean). Also there is no indication on the engine block. Any suggestions on how to find a leak tht is not obvious?

 

You could get the car pressure tested and that will locate a leak quickly, but I also kind of would suspect the UIM or LIM gasket

Though it could also be the water pump, but I'm sure you could see the coolant from that near the passenger wheel

 

My oil never had any signs of coolant in it and it was the LIM gasket and I replaced the UIM gasket at the same time of course. I use to have to add coolant about once a month; now it holds steady.

 

--At this point this is what I have:
All fuses chked out ok.
No power going to the fan motor.
Changed the relays (of course I saw the post about switching them after i had bought them)

--Possile diagnosis:
the PCM or wire(s) to the PCM. I need to chck if the relays are putting power to the PCM. What do you think?
I would think it was th gasket but it's not loosing coolant.

--Any more advice will be much appreciated : )

 

the temp sensor also helps tell the fans to turn on. but i will do the simple things first change all the hoses hose down the out side of the radiator do to debrise colecting in front of it like leaves bugs dirt things like that. also change out the thermostat do to it may be one way to hot for it or not the right type. after doing that change the water pump and see if that fixes it. if it didnt it is the uim or the lim but first things first presure test. to help narrow it down the problem as well

 

I just worked on my my fathers 2000 impalla w/ the 3.4. It has the same overheating problems. It has 150,000 miles and the fans don't turn on, unless the ac is on and then it is only 1 of the fans. I changed all 3 of the relays, the temp sensor, and had the system flused and it has no leaks. I am still confused why the fans wont turn on at all. So were in the same boat does anyone have any input?