96 Deville Overheating. Only overheats while driving. Will sit hours & not get hot.
I've looked at several posts and still can't find anything like what's going on. My 96 deville overheats ONLY when driving & ONLY when the a/c is turned on. I can let it run in the driveway forever even with the A/C on and temp is fine. I can drive it around without the a/c on and it is fine. But if I turn on the A/c it starts overheating quickly. Had it in the shop, replaced the radiator, said waterpump is fine, all relays were fine, thermostat replaced just in case. But still gets hot. The fans only run low when the A/c is on. But I disconnected the high side pressure switch & the fans immediately came on high when I turned the a/c on. I drove it up the rode a few miles but it overheated again once I turned on the a/c even though the fans were both going on hi. So I guess it is not getting hot because the fans were not running on high. The codes I got are PC 0151 and 0717. I looked those up and see the 0717 is a sensor in the transmission. The sensor may be out but the car transmissions runs perfect, no problems. I see the 0151 code is a 02 sensor. Any suggestions on what could be causing it to overheat only when I drive it with the a/c on. I can let the car idle in the driveway for an hour WITH the a/c on and it never gets hot...only when I actually drive it down the road WITH the A/C ON. If it starts overheating, I turn the a/c off and the heater on and the temp goes back down.
I've looked at several posts and still can't find anything like what's going on. My 96 deville overheats ONLY when driving & ONLY when the a/c is turned on. I can let it run in the driveway forever even with the A/C on and temp is fine. I can drive it around without the a/c on and it is fine. But if I turn on the A/c it starts overheating quickly. Had it in the shop, replaced the radiator, said waterpump is fine, all relays were fine, thermostat replaced just in case. But still gets hot. The fans only run low when the A/c is on. But I disconnected the high side pressure switch & the fans immediately came on high when I turned the a/c on. I drove it up the rode a few miles but it overheated again once I turned on the a/c even though the fans were both going on hi. So I guess it is not getting hot because the fans were not running on high. The codes I got are PC 0151 and 0717. I looked those up and see the 0717 is a sensor in the transmission. The sensor may be out but the car transmissions runs perfect, no problems. I see the 0151 code is a 02 sensor. Any suggestions on what could be causing it to overheat only when I drive it with the a/c on. I can let the car idle in the driveway for an hour WITH the a/c on and it never gets hot...only when I actually drive it down the road WITH the A/C ON. If it starts overheating, I turn the a/c off and the heater on and the temp goes back down.
