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Q: heater core flush on 1996 Ford F-150

how do you flush the heater core? while ideling gets warm. driving gets cold. has new thermostat, but will not get the cab warn at all.
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May or may not be a heater core issue. How are the inlet and outlet hoses? Is one cold and one hot? Or are they both the same temperature? The only indication of a heater core restriction is if the inlet hose is piping hot and the outlet hose is cool.

To flush, you basically force water into the core either way and allow it to come out. Both hoses have to come off. You probably want to hook up some hoses to flush through, though, so that your water and coolant do not go everywhere.

When you're done, you need to purge the air out of the cooling system after everything is hooked back up.
Thank you Dave. I will try this. Both hoses get warm, bot one get warmer than the other until you turn the heat on then they both get cold. I'll dissconnect then and try the flush and pray that it will work. I'd hate to have to do a core replacement here in the freezing cold of Kansas city while outside. Thanks again.
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