Originally Posted by Mike1995
There are only 4 things that can cause an overheating issue.
1. Sticking or upside down thermostat.
2. Lack of coolant.
3. Faulty water pump(vanes rotted away-but unlikely due to age of car)
4. Or gummed up cooling system.
I'll add a few more:
- Blown head gasket. The oil may or may not be milky. Check it.
- Fans not coming on. Could be a bad ECT sensor, low speed relay, high speed relay, fan motor, etc.
- Rad cap not sealing to rad filler neck. You have a sealed and pressurized coolant system. If open to atmosphere the coolant will boil at a lower temperature.
- Overflow reservoir cap not sealing. Same comments on sealed system.
Some Grand Am owners have corrected this with installing a new overflow and reservoir ($30???). Blown head gaskets are a common issue with your engine. If your local Autozone has a coolant pressure tester, pump it up to the recommended pressure to see if it holds or bleeds down.
Try bleeding the coolant system while parked on an up-hill slope.
2001 Bonneville SSEi (retired at 365,000 Kms.)
2014 Jeep Grand Cherokee Overland (yes, I know its not a GM)