Question about 2001 Chevrolet Silverado 2500HD

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Air pocket in coolant system

Fan blows good but no heat

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  • swissmade59 Feb 28, 2009

    ford /focus 2002 put in a thermostat can't get air pocket out what now

  • Richard Delahant May 11, 2010

    try having the system bled of any air build up. There are 2 other things to have checked----- there should be a vacuum operated actuator valve that opens the heat vent door, and the heater control valve. The acuator valve is under the dash usually up and behind the ac ducts.


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Loose Radiator or coolant cap in cold and have the car idle for five minutes with out the cap, or have the car idle for 10 minutes, wile running remove cap, let air pressure out and put cap back, do it 3 or 4 times till all air is out...

Posted on Jan 22, 2009

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Air pocket need the thermostat housing.

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You may want to reconsider if the fan is working at it's full potential.It seems when the vehicle is moving the extra air flow compensates for the fan not blowing hard enough.Check for radiator obstructions such as leaves and debris.And check for small leaks.Also there may be an air pocket in the system which can still seem like the system is full.With vehicle cold take off radiator cap and run vehicle.Turn on heat to highest setting (blowing).When vehicle reaches thermostat rated temperature(opened thermostat) you will see coolant go down in radiator.Fill radiator while the engine rpm's are up (have someone hold the throttle to where the rpm's are at about 1800) then put on cap before returning to idle.This should remove the pocket if there is one

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Most likely you have a bad thermostat is stuck and not letting coolant to flow to your radiator. check your coolant level if is normal replace the thermostat NOTE: if you live air pockets on your cooling system then also cause to over head when adding new coolant open the bleeder valve if you cant find it just add coolant whit the engine running when the new thermostat open will release the air pocket and you will see a sudden drop of you coolant level, then add more on till the radiator is full again. never drive your car for long is your engine is over heating that will cause a blown head gasket and mayor repairs. if your on the street and just notice than your car is over heating turn your A/C off set it on heating maximum fan max heat and of coarse roll down all your windows. it be real hot for you but that will save your engine. the heater core on your car is like a baby radiator and bypass the engine thermostat that will help to cooled down a lot . hope this help you and good luck.

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When u flushed the radiator, what did u find? Was the old coolant dirty, rusty, sediment in it? What u describe sounds like the core is plugged up w/ junk. This would be my 1st choice of the problem, especially if the coolant was rusty, cruddy, as described above. It wouldn't be an air pocket (after a couple of years). Some cars do have a valve that opens and closes to allow the hot coolant into the core for heat, or a flap door that opens to allow the fan to blow air thru the core for heat, but the fact that this started when u flushed the system leads me to believe it's a plugged up core. U could try to flush the system again, make sure the heat is on when u do, so u have circulation tthru the core to help flush it out. let me know how u make out. good luck!

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