: 2000 Deville DTS Overheating

02-12-08, 12:54 PM
I have a 2000 DTS with 117,000 miles on it. I am haveing a temp issue with the car. I can drive the car with the heater on the heater will get cold and then the temp hand will go up. After a while the heater will get back hot and the temp hand will go down. Also as long as the car is setting still the temp will stay down. I have replace the radiator, water pump and the thermostat. Any ideas of what the problem could be?

02-12-08, 03:42 PM
Do a search for "Purge Line". Sounds like you have air in the system.

02-12-08, 06:43 PM

02-12-08, 08:35 PM
Look down about 7 or 8 post for "Overheating". Mine is doing the exact same thing.



02-12-08, 08:37 PM
Could be an intake gasket as well. I just repaired the intake gasket on my conversion van and it did the exact same thing your car is doing. I didn't overheat but it ran a lot hotter than usual plus when I turned on the heat it would come out hot then cold like yours.

02-15-08, 07:11 PM
Is the car new to you? This is also a symptom you get when someone adds "heal-a-seal" in a can to the coolant system. It never fixes the head gasket and it almost always plugs the heater core the rad or both.