I have a 98 Pontiac Sunfire (2.2L). I have replaced the thermostat and the water pump. I have checked for signs of water in the oil and found none. It is still overheating. There are no signs of leakage that I have found. It has 130,000 miles. The hoses are do not seem to be under any pressure while running. (I can squeeze the hoses with my hand.)


(This post was edited by carjunky on Nov 17, 2009, 2:37 PM)

When is it overheating?
How hot does it get?
Are you losing any coolant?




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It is overheating while driving. The temperature gage pegs out. No coolant lost due to leakage, maybe some due to overheating.

The first thing you want to look at is the condition of the radiator. The symptoms would indicate either a radiator that just doesn't have the cooling capacity or a blown head gasket from a previous overheating.




78 Corvette Pace Car For Sale-18k mi orig-Florida

This the first overheating issue I have had since ownership. Three years. The capacity of the radiator should have come into play before now shouldn't it? Thanks for your assistance.

Does it cool down when the car stops in traffic?




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No, it does not cool down at all. I can't drive more than a mile without the temperature redlining. During the first overheating, two days ago, it seem to cool down some (not much)while driving 55 - 60. I attributed that to air cooling.

the radiator could be clogged

What is the mixture of coolant?
Have you done a drain and flush on the system?
Changed the thermostat with the correct thermostat?
I have had thermostats bad right out of the box!