I have a 2003 H2 Hummer. A few months ago the the readout on the instrument panel said the "engine coolant hot". Since then I have replaced the water pump, the heat sending unit, the clutch fan and the thermostat. After all of this, after about thirty minutes of running the instrument panel still says "engine coolant hot" Does anyone out there have any idea what is going on or how to fix this problem?

 

Normal driving conditions or were u flying down the road when that happened? Also was your a/c on? Does it still happen now? Try a heavyduty fan clutch Idk so many possibilities.

 

I was driving about 35 MPH and when I pulled into a gas station to fill up it overheated. I only drove about 3 miles from the house when it happened.

 

Also, my A/C was off.

 

Only 35 MPH and 3 miles sounds bad. Are you getting any white smoke from the tail pipe? Sweet smelling exhaust? Could have internal coolant leak. Spendy repair.

 

None of the above symptoms exist but the engine runs and sounds great it just overheats. I do have 135,000 miles on it though.

 

If there are no external coolant leaks, and stone cold, the engine is over heating within a few miles/minutes, there is a good chance you have a internal leak. May be a head gasket just starting to fail. This will allow the combustion to enter the coolant system and super heat the coolant very quickly. This can be checked quickly by a garage if they put in a dye and test for carbon monoxide escaping the coolant recovery tank. Good luck and don't put any "sealers" in your coolant system.

 

Thanks for the information.

 

If u do sealer trade her in and let a dealer deal with it=}

 

Could be low on antifreeze from leak from h20 pump,hose radiator,heater core,ect, fan can not be coming on, thermostat can be sticking, bad head gasket, faulty gauge...check the obvious stuff first... Good luck!