Very little heat

2000 GMC SONOMA
103,000 MILES • 4.3L • 6 CYL • 4WD • AUTOMATIC
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GEORGE RHODES
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I replaced heater core last year.had good heat.this year has lukewarm heat.I checked heater core hoses one is hot the other is warm.new thermostat last year also.antifreeze is full.thanks
Sep 17, 2020 at 4:17 AM
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ASEMASTER6371
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Good morning,

Sounds like some dirt or debris got into the heater core.

https://www.2carpros.com/articles/car-heater-not-working

I would remove the hoses from the core and use a garden hose to flush the core back and forth several times until you get a clear even flow from both sides.

https://www.2carpros.com/articles/replace-heater-hoses

Also, make sure the coolant level is good as well.

https://www.2carpros.com/articles/radiator-pressure-test

Roy
Sep 17, 2020 at 4:50 AM
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GEORGE RHODES
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Thank you, I'll try it .
Sep 17, 2020 at 4:54 AM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
Sep 17, 2020 at 5:02 AM
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GEORGE RHODES
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Hello ACEMASTER6371.I flushed heater core.and replaced thermostat.heater core was a little dirty.thermostat housing was right there and easy to get to where I disconnect heater hoses.so I replaced thermostat also.I have great heat.thank you.have a Blessed Day!!
Sep 17, 2020 at 11:16 AM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
Sep 17, 2020 at 12:22 PM