changed thermostat, still overheating

Dwalk08 · 05-22-2008, 09:16 PM

so i have had the overheating problem off and on, some days it runs normal, and some days its gets hot, but only about 3/4 of the way to the red then drops back down to normal. First thought was the thermostat so today I took the housing apart, replaced the thermostat and gasket, put it back together and it ran normal for a while. On my way home, which I drove about 30 miles the car started overheating again and worse than before i had installed the new thermostat. It would go back to 3/4 hot and stay there for 5 or 6 minutes then return to normal. The high speed fan was running and nothing happend. Any ideas?

How do I bleed the radiator on this car? Could that help? The thermostat that I installed was the correct one for this car.

Vix · 05-22-2008, 09:39 PM

Could be the relay or fuse. I would check the ground wires as well located below the battery too.

skater · 05-22-2008, 09:49 PM

I'd go into the diagnostic mode and see what it is reporting there for the temperature. IIRC our cars actually have two sensors - one for the gauge, and the other for the computer, which is what is reported in diagnostic mode. I have a sneaking suspicion that you'll find that the actual coolant temp is fine and it's a gauge problem.

Dwalk08 · 05-22-2008, 09:57 PM

how do i get to that diagnostic mode and temp reading?

Dwalk08 · 05-23-2008, 10:28 AM

okay so i literally drove 10 minutes and the temp guage was up at 3/4 but then dropped back to normal. when i refilled after i replaced the thermostat i put straight coolant in and then some water...could the concentration of coolant mess with the gauges? the car doesnt feel any hotter than usual, but the fans are on the whole time its running

skater · 05-23-2008, 11:45 AM

Okay - if the fans are on the whole time then the computer thinks it's overheating.

The mix COULD affect it but that's probably not your problem. You should have 50/50 in there.

Possible solutions: water pump, thermostat, clogged radiator, clogged hose...

An air bubble could cause it, too, but that should work itself out in a day or two of driving.

Diagnostic mode:

Quote:

On the 1999 and 2000 EEC-V Engine Management System, you can access the Diagnostic Mode by Pressing (RESET) and (UNITS) at the same time while turing on your car. Let go as the dials spin to the right. You scroll through the modes by pressing the (SELECT) Button

Dwalk08 · 05-23-2008, 04:41 PM

well the relays are fine and the fans are kicking on when they are suppose to. I ran the diagnostic at it was running 220/225 degrees and it maxed at 230 degrees. I am parking it for now until I can look at everything more closely, I hope its just an air bubble cause this car is breaking my wallet.

rjnredxr7 · 05-23-2008, 08:55 PM

it sounds like air to me and i dont think it will work itself out . I always use one of those tools to pull a vacume and fill it back up.

Dwalk08 · 05-25-2008, 08:45 PM

where is the radiator drain plug on this car? if anyone has a pic that would be great!

Gorman · 05-25-2008, 10:09 PM

you might want to check to water pump impellar....G.

05-22-2008, 09:16 PM	#1 (permalink)
Dwalk08 NECO Member Join Date: Jan 2008 Location: Owensboro Kentucky Posts: 24	changed thermostat, still overheating so i have had the overheating problem off and on, some days it runs normal, and some days its gets hot, but only about 3/4 of the way to the red then drops back down to normal. First thought was the thermostat so today I took the housing apart, replaced the thermostat and gasket, put it back together and it ran normal for a while. On my way home, which I drove about 30 miles the car started overheating again and worse than before i had installed the new thermostat. It would go back to 3/4 hot and stay there for 5 or 6 minutes then return to normal. The high speed fan was running and nothing happend. Any ideas? How do I bleed the radiator on this car? Could that help? The thermostat that I installed was the correct one for this car.

05-22-2008, 09:39 PM	#2 (permalink)
Vix NECO Member Join Date: Jul 2006 Location: somewhere, ut Posts: 1,056	Re: changed thermostat, still overheating Could be the relay or fuse. I would check the ground wires as well located below the battery too. __________________ Please read the signature rules! Banners must be smaller than 100 tall/600 wide, and under 20k in filesize! Sorry, but i guess that's a hard thing to do when you have jugz like those.

05-22-2008, 09:49 PM	#3 (permalink)
skater Capital Curmudgeon Join Date: Aug 2003 Location: Bowie, MD Posts: 6,485 Images: 3 Blog Entries: 1	Re: changed thermostat, still overheating I'd go into the diagnostic mode and see what it is reporting there for the temperature. IIRC our cars actually have two sensors - one for the gauge, and the other for the computer, which is what is reported in diagnostic mode. I have a sneaking suspicion that you'll find that the actual coolant temp is fine and it's a gauge problem. __________________ 1999 Cougar, Laser Red, 2.5L V6, MTX / 2004 Impala, Superior Blue, 3.4L V6, ATX / 1991 Airstream B190 7.5L V8

05-22-2008, 09:57 PM	#4 (permalink)
Dwalk08 NECO Member Join Date: Jan 2008 Location: Owensboro Kentucky Posts: 24	Re: changed thermostat, still overheating how do i get to that diagnostic mode and temp reading?

05-23-2008, 10:28 AM	#5 (permalink)
Dwalk08 NECO Member Join Date: Jan 2008 Location: Owensboro Kentucky Posts: 24	Re: changed thermostat, still overheating okay so i literally drove 10 minutes and the temp guage was up at 3/4 but then dropped back to normal. when i refilled after i replaced the thermostat i put straight coolant in and then some water...could the concentration of coolant mess with the gauges? the car doesnt feel any hotter than usual, but the fans are on the whole time its running

05-23-2008, 04:41 PM	#7 (permalink)
Dwalk08 NECO Member Join Date: Jan 2008 Location: Owensboro Kentucky Posts: 24	Re: changed thermostat, still overheating well the relays are fine and the fans are kicking on when they are suppose to. I ran the diagnostic at it was running 220/225 degrees and it maxed at 230 degrees. I am parking it for now until I can look at everything more closely, I hope its just an air bubble cause this car is breaking my wallet.

05-23-2008, 08:55 PM	#8 (permalink)
rjnredxr7 NECO Member Join Date: Mar 2004 Location: tifton Posts: 15	Re: changed thermostat, still overheating it sounds like air to me and i dont think it will work itself out . I always use one of those tools to pull a vacume and fill it back up. __________________ richard nelson

05-25-2008, 08:45 PM	#9 (permalink)
Dwalk08 NECO Member Join Date: Jan 2008 Location: Owensboro Kentucky Posts: 24	Re: changed thermostat, still overheating where is the radiator drain plug on this car? if anyone has a pic that would be great!

05-25-2008, 10:09 PM	#10 (permalink)
Gorman NECO Member Join Date: Mar 2006 Location: London, U.K. Posts: 742 Images: 5	Re: changed thermostat, still overheating you might want to check to water pump impellar....G. __________________ 2.5L MTX. SVT ECU. Cold air feeds. 65mm P+P TB. Port matched SVT upper to SVT LIM. MSDS Headers. Optimized Y pipe. Test pipe. Wish list. 4X4 wtb xcal

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