First off i have a 2000 Monte Carlo LS. My car has been acting a little weird lately. Ive intermitantly had a low coolant light on in the dash. It usually doesnt come on until Ive been driving for about 5 minutes and seems to go off when I turn the AC on. Just recently the car has been running around 220 when it usually is 160 or so.

I had the coolant system flushed out a month ago and after the system was flushed the low coolant light was still on...thus bad sensor correct? Now all of a sudden the car heats up very fast to about 220 and stays there with no difference in traffic or on the highway. Today I tried to turn the heat on and it only blows cold air? The coolant level is fine so whats up? Is it the heater core? Thermostat?

How do you get to the thermostat on these cars?

 

This is a simple fix. Start the car, turn the heat on and let it run for about 15 minutes, take the radiator cap off before doing any of this and top it off with coolant if it appears low. Once the car has run for about 15 minutes open the AIR BLEEDER screw on top of the thermostat housing. At first you may not see any coolant coming out when the bleeder is open, leave it open and throttle it up somewhat hard a few times and check to see if your getting some heat, also check the level in the radiator to see if its dropped, it more than likely will as the air that is being displaced makes room for more coolant. once youve begun to get heat let it run for about another ten minutes every few minutes opening the bleeder screw and making sure you see a steady stream of coolant. Hope this helps.

 

Sounds to me that you may have a leaking intake. I would check it out soon.

 

Thats vert true, but also 1000 bucks to fix at most dealers or shops. For now it needs to be bled of the air and filled with coolant otherwise the intake gasket will be the least of your worry. There has to be MILLIONS of 2.8 3.1 and 3.4 that never got fixed, what a shame gm never caught that problem early on, it spans for way to many years, makes ya wonder if its a desgined falw to get money out of 50 percent of the cars on the road..lol

 

orthokneepa,
I just replaced the intake gaskets on a 2000 impala with a 3.4 two weeks ago (customers car). This is a very common complaint on these cars ( just something to be looking for). There are several factors that could be causing the high temps, some of them have been noted by others in this thread. I would verify that the electric fans are operating properly, if I'm not mistaken the fans operate at different speeds dependant on if you are running the A/C or not (make sure they kick on as the car gets up to temp). I would also check the oil level to make sure that you are not losing coolant (oil & water makes a nasty milkshake) into the engine via those intake gaskets creating a very bad situation inside the motor. Have you noticed any leaks under the car? I asked this because 1 week after I did the intake gaskets on the car the water pump started leaking and had to replace that also (it was the next weak link I suppose).
On your car (if its a 3.4 the thermostat can be accessed just under the throttle body where the upper radiator hose connects. You should be able to remove the top bolt and just loosen the other bolt enough to remove the housing (you dont have to take it all the way out as the thermo housing is slotted to help slide it away from the exhaust pipe that is in the way).
Hope this helps

 

I will check the car out today guys now that I have a chance. I did add some coolant yesterday and it seems to have taken the temp down a bit. Whats funny is about 15K miles ago one of those quick oil change places said I may have an intake leak but Ive asked everytime since and no one seems to find anything. I will report back after today.

 

I added some coolant today and again the temp seems to drop. I added about 1 liter and took the car for a drive. When I came back the level in the radiator dropped again so I added another liter. The low coolant light keeps coming on though? Im going to try to bleed any air out now.

Also in regard to the intake. Im very unfamiliar with these cars (although I built and installed a 383 LT1 in a 96 camaro). Is the intake purely what attached to the throttle body going to the heads? I just took a quick look but the fuel rails are under the intake also correct? Im used to the other way around with the f body's.

Ill report back again..

 

orthokneepa,
I would think that 2 litres of water has to be going some where. Are you adding to the radiator or the overflow bottle, the O/F bottle could posible be cracked too. Here is a pic of where the fuel rail is that you asked about. Have more pics if needed let me know
BnB SS

[IMG]local://upfiles/1352/3273B322B3404EDDA0D8EAA8C1713C82.jpg[/IMG]

 

Thanks for the pic. Yeah I dont understand it either unless it was just WAY low. I bled some more air out today and the temp again seems to be lower and steady. Still a low coolant light though????

 

This really is starting to drive me nuts. Over the course of the past week Ive filled and bled the coolant system two times. I still intermittantly get a low coolant light though. Ive ruled out the thermostat since the car cools fine with added coolant, the light just wont go off.

Yesterday added more coolant to the radiator and bled the system multiple times. I then turned the car on and no light! for 10 minutes with the car idling. I then took a 10 min ride to the store and sure enough the light popped on again. The temperature is perfect, heat works, etc.

Any friggen idea. Im loosing coolant somewhere but the oil looks fine, no white smoke out of the exhaust and no leak obvious to a good inspection with the bare eye. Ive added almost 3 liters of coolant in the past 10 days.

Any idea?????