My heater will not blow hot air slightly warm.

Tiny
NATEBOLDT19
  • 1988 CHEVROLET S-10
  • 164,663 MILES

My heater will not blow hot air slightly warm but thats it changed thermostat already and flushed out heater core but still not working properly

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Wednesday, January 30th, 2013 AT 4:40 PM

8 Replies

Tiny
WRENCHTECH
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  • 20,566 POSTS

With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If they are both hot, the heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

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Wednesday, January 30th, 2013 AT 5:13 PM
Tiny
NATEBOLDT19
  • MEMBER

Where is the actuator located and is it a big job I have done a majority of the work myself so just wanting to save money

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Wednesday, January 30th, 2013 AT 5:45 PM
Tiny
WRENCHTECH
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One step at a time. Do the other checks and we'll go from there.

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Wednesday, January 30th, 2013 AT 6:03 PM
Tiny
NATEBOLDT19
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I just had the truck up to temp and the one going to the engine from the heater core is warm but the one going from the rad to the heater core is cold

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Thursday, January 31st, 2013 AT 1:33 AM
Tiny
WRENCHTECH
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That's indicating a plugged up heater core, probably from old dexcool getting sludged up.

You can remove the heater hoses and try to flush the core with water pressure from a garden hose but if the engine is dirty too, it will get plugged up again quickly.

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Thursday, January 31st, 2013 AT 1:37 AM
Tiny
NATEBOLDT19
  • MEMBER

I tried to flush it and it seemed to go warm but then cold again how do I clean everything out would it help if I drain all the rad fluid and rinse them out then rinse the heater core out again and refill it?

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Thursday, January 31st, 2013 AT 1:51 AM
Tiny
WRENCHTECH
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It's going to take some chemicals and professional flushing to get the rest of the cooling system clean and even then it may not come clean because it's just too crusty.

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Thursday, January 31st, 2013 AT 1:54 AM
Tiny
NATEBOLDT19
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Hmm nnow what to do haha

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Thursday, January 31st, 2013 AT 2:08 AM

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