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cracked head gasket; blockage in radiator pipes, could be anything
If it slowly overheats as you drive then the cooling system is probably struggling to keep the engine at running temp. A number of things can cause this.
Coolant leak
- you said there were no drips so this can be ruled out
- coolant leaks will also create vacuum leaks that let in air and then the coolant wont circulate properly
The coolant could not be circulating fast enough.
- bad water pump, impeller could be slipping on the shaft
- cholesterol in the radiator, restricted flow
Very old coolant looses its ability to absorb heat
- do a coolant flush (cheapest and first thing to try)
Sticky thermostat
- the thermostat is stuck reading that the engine is always "cool" so it doesn't kick on the fans (if you have them)
Blown head gasket (worst case/ biggest P.I.T.A.)
- coolant is seeping into the cylinders and places where there is oil (vice versa)
- this will cause white smoky exhaust, vacuum issues, engine will consume coolant, loss in power, run cylinder compression test to check head gasket health.
Radiator fans are slipping.
Bad coolant temperature sensor that sends temperature to the car's computer.
There are probably some other factors that I have overlooked, but look into these and you should find a problem. All cars are different. Some of this may not apply.
check your coolant level when the engine is cold
I have a 2005 Grand AM SE, 3.4L. The past two days the temperature gauge has been higher than normal, around 200 degrees. It's normally not that high, and I slowly keeps climbing. I let it cool off for over 4 hours and checked the antifreeze level and it was full. We also checked to see if it was leaking, but there was no sign of it leaking on the cement either. What would cause my car to start getting so hot? Please help, I'm going to be away from home for around a month in the next couple of days and I need my car to be working properly.
