Grand Prix starts to run hot with ac turned off
- Thread starter DreamerGT
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Obviously, the AC fan is keeping things cooler.
It is tough to see the radiator fins, as the condenser is blocking the view.
Water flush them with low pressure when the car is cool - maybe a SOFT brush..
Maybe you can shift the condenser out of the way by removing a few bolts temporarily.
What else? low coolant, faulty WP or belt, and faulty thermostat are possible.
Still, it is good to have the condenser and radiator clean - a good start no matter what.
It is tough to see the radiator fins, as the condenser is blocking the view.
Water flush them with low pressure when the car is cool - maybe a SOFT brush..
Maybe you can shift the condenser out of the way by removing a few bolts temporarily.
What else? low coolant, faulty WP or belt, and faulty thermostat are possible.
Still, it is good to have the condenser and radiator clean - a good start no matter what.
I had this same problem with my 1995 grand prix 3.1L V6. When stopped with the AC off, the engine would climb up to the red. Turning the AC on, revving the engine for 10-20 seconds, or waiting for the engine temp to come really close to the red mark and kick on the extra fan would correct the issue and it would go back down to the half way mark. As soon as you stopped revving, turned the AC off, or that second fan turned off it would climb again. This cycle would repeat. I assumed it was a coolant flow issue but as it never caused that pile of junk to explode into fiery death I was disappointed.. err I mean... as it never caused a major functional problem I did not investigate further.
cheack and make sure you fan(s)s are working with the a/c off
Yep, I would guess the fan isn't kicking in by temperature. My [dated] GM experience was that the fans would always kick in when A/C was turned on, assuming the fans were working in the first place, so if a sensor is shot, that may be the culprit.
I would guess what he said. Some cars have two electric fans, one that runs due to coolant temperature, and one that runs when the A/C compressor is engaged. This sounds a lot like the regular coolant fan is inop and you are only getting fan airflow when the A/C is on.
Originally Posted By: mattd
does that car have 2 fans? If so, check for seized or inoperative cooling fan. It runs cooler with A/C on because of condenser fan.
Originally Posted By: mattd
does that car have 2 fans? If so, check for seized or inoperative cooling fan. It runs cooler with A/C on because of condenser fan.
Agreed with the above posters. Also, sometimes there is high and low speed operations (high for A/C or really hot engine temps.. low for normal cooling); and a bad relay will not allow low speed operation.
GM is also good for letting the temp gauge go to 80% of red or even higher before the fan kicks on automatically. Scares the drivers. This buys them a little MPG on the EPA test cycle: the car sits in "traffic" not long enough to overheat but the lack of fan helps the thermal efficiency.
Originally Posted By: eljefino
GM is also good for letting the temp gauge go to 80% of red or even higher before the fan kicks on automatically. Scares the drivers. This buys them a little MPG on the EPA test cycle: the car sits in "traffic" not long enough to overheat but the lack of fan helps the thermal efficiency.
Sounds good.
This is also why Ford has the dual temp thermostats - hot for cruise, and 'down' to 195 for power.
GM is also good for letting the temp gauge go to 80% of red or even higher before the fan kicks on automatically. Scares the drivers. This buys them a little MPG on the EPA test cycle: the car sits in "traffic" not long enough to overheat but the lack of fan helps the thermal efficiency.
Sounds good.
This is also why Ford has the dual temp thermostats - hot for cruise, and 'down' to 195 for power.
Ok.. What is "running hot" to you? Is this a new thing?
Are you over-heating? Or just getting "up there" in the temperature range (not in the red) before the fans come on? Most of mine with reliable gauges get to about 3/4's up before the cooling fans kick on and bring it back down the middle.
Having the fans continue to run for a bit after shutting off the AC is normal on most cars IIRC.
Are you over-heating? Or just getting "up there" in the temperature range (not in the red) before the fans come on? Most of mine with reliable gauges get to about 3/4's up before the cooling fans kick on and bring it back down the middle.
Having the fans continue to run for a bit after shutting off the AC is normal on most cars IIRC.
Originally Posted By: eljefino
GM is also good for letting the temp gauge go to 80% of red or even higher before the fan kicks on automatically. Scares the drivers.
Yep, 1996 Chevrolet Caprice police package was a fine example of this one.
It would go way high, then kick in, and go way back down, and repeat, during idling.
GM is also good for letting the temp gauge go to 80% of red or even higher before the fan kicks on automatically. Scares the drivers.
Yep, 1996 Chevrolet Caprice police package was a fine example of this one.
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