I bought this car about a month ago with an overheating problem it couldn't travel for 3 miles without overheating after replacing the thermostat and gasket. The previous owners cut away the thermostat and left the ring for the gasket.

After flushing the system completely and getting all kinds of junk/gunk out of it until it ran clear. I put the old piece and new gasket back in and it will run fine until it gets to a hill. Found out the water pump needed changed. Just got done changing it and switched to the new thermostat and it is back to overheating again after 3 miles. The system has been bled of air every time.

I am wondering what I should do now I have found no signs of a head gasket leak or water leaking anywhere. What should I do now? My mechanic and I are thinking two different things. They think a plugged radiator while I'm thinking the Temperature sensor switch. I'm about to go back to the cut up thermostat. Any thoughts?

  • 1
    Where do you live (I.e. What is the elevation there?) if you have a bad radiator cap (One that doesn't seal correctly) and you are at high elevation coolant will totally boil away at lower than normal operating temperatures. I'd sure like to see a photo of the bottom of your radiator cap.
    – zipzit
    Commented May 3, 2016 at 8:09
  • Does running the heat help? If you feel the radiator when the engine is hot, are there any cold spots?
    – rpmerf
    Commented May 4, 2016 at 12:06
  • yes the cap has been replaced so has the water pump and the thermostat i live in colorado springs. when it is cold out it has been running fine. now that it is hot out it can run about 11 miles before over heating or when i get past 50 mph
    – mike
    Commented May 7, 2016 at 4:19

1 Answer 1


Lack of system flow or a radiator that cannot transfer heat are the only real options remaining. But since the water pump and thermostat are new and there are no air bubbles in the system the system should be able to flow freely as long a the radiator is not plugged.

The most likely cause the overheating is a plugged radiator. A nearly 20 year old radiator is always suspect. They are relatively inexpensive and easy to change.

Why the fans are an unlikely cause. The radiator sees more than enough air flow while driving; the fans are not needed and in fact should not come on. Cooling fans should only come on when the vehicle is not moving.

  • "Cooling fans should only come on when the vehicle is not moving." Not always true.
    – Moab
    Commented May 3, 2016 at 15:59
  • @Moab I agree and considered putting the cases for the fan on while rolling but decided to keep it simple. Commented May 3, 2016 at 20:20

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