Temperature gauge hot

CARSON123

MEMBER
2003 CHEVROLET MALIBU
3.1L
6 CYL
FWD
AUTOMATIC
88,000 MILES

My gauge reads hot or 250 after running for twenty minutes and sometimes less. Nothing is hot, hoses, overflow tank. Not boiling over. We changed water pump. Thermostat factory rated 195 degree. Coolant sensor. Still doing same thing temperature gauge goes to max and alarm dings. So we bought temperature scanner tool it reads upper radiator hose at 148 and lower hose at 135 and overflow tank about same degrees. Car does not and never has leaked any fluids. Oil has no water in it. Does not smoke at all. Any ideas please?

Tuesday, May 30th, 2017 AT 6:03 PM

1 Reply

WRENCHTECH

MECHANIC
20,761 POSTS

Those infrared temperature tools do not read through rubber hoses. You need to take a reading on the metal on and around the T-stat housing.
You also should use a scan tool to see exactly what temperature is being reported to the PCM because 230 would be normal. 250 would not. The cooling fans are programmed to come on around 226-228 degrees. You have to be very careful with air pockets on that engine. They are notorious for air pockets and blown head gaskets.

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Tuesday, May 30th, 2017 AT 6:36 PM