all heat settings blowing cold air except max
#1
04-01-2012, 12:56 AM
Join Date: Mar 2012
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#2
04-01-2012, 09:51 AM
How many miles on your truck? If over 100k miles, when was the last time you did a complete coolant change/flush?
It sounds like it might be a plugged heater core which is typically caused by dirty coolant. If you are close to or beyond 100k miles, i would suggest a full coolant flush. Turn the heat on in the truck and then shut it down. Make sure the truck is cool. Drain the entire system from the radiator Petcock, then the lower radiator hose.
Once the system is drained, disconnect both heater hoses at the front of the block. Using a garden hose at a low setting (do not turn it on full blast, you can cause damage) hold the hose against one side of the heater hoses to push fresh water through the heater core. Do this on both hoses (one at a time obviously) untill the water is running out clear with no signs of coolant or debris. If the water flows freely in and out of the heater hoses, you have confirmed that the heater core is not plugged (or if it was, it's not any longer).
If you did see solids in the coolant and when you look in the radiator you see corrosion on the core, then use a cooling system flush chemical in the system and follow the instructions on the bottle.
It sounds like it might be a plugged heater core which is typically caused by dirty coolant. If you are close to or beyond 100k miles, i would suggest a full coolant flush. Turn the heat on in the truck and then shut it down. Make sure the truck is cool. Drain the entire system from the radiator Petcock, then the lower radiator hose.
Once the system is drained, disconnect both heater hoses at the front of the block. Using a garden hose at a low setting (do not turn it on full blast, you can cause damage) hold the hose against one side of the heater hoses to push fresh water through the heater core. Do this on both hoses (one at a time obviously) untill the water is running out clear with no signs of coolant or debris. If the water flows freely in and out of the heater hoses, you have confirmed that the heater core is not plugged (or if it was, it's not any longer).
If you did see solids in the coolant and when you look in the radiator you see corrosion on the core, then use a cooling system flush chemical in the system and follow the instructions on the bottle.