Heating problem help please

Discussion in 'The Garage' started by Wayne Barnes, Oct 9, 2017.

  1. Wayne Barnes

    Wayne Barnes New Member

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    2000 GMC Sierra 1500 four-wheel-drive with the 5.3 .......Like the title said I have heating problems During the summertime I did not run the heat Now that it’s cooling off I started trying to run the heat I got cold air.... so I check the water level and left the cap Off and ran it The heat was blowing fine was really hot then I have put the cap back on the radiator or the bottle and within 5 to 10 seconds the heat went away To like lukewarm I really don’t know what’s going here. I have flushed the heater core out putting water back in it let it run with the cap off hot heat Then I thought I had it fixed so I put the cap back on and driving down the road and then with in five minutes it was like cold again I don’t know what’s going on please help me??????? Thanks in advance

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  2. Loki

    Loki Knuckle Buster

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    so...a few things to find out here...

    - are you adding antifreeze with the water or just water (should be distilled)
    - is the truck coolant temperature gauge rising to 187/190*? (does it overheat)
    - are there any leaks that you've noticed?
    - does it smell like coolant in the cab with the truck running and the heat on
    - is there any evidence of water/coolant on the passenger side floor board? (might have to pull up the floor matt)
    - have you scanned your truck for codes

    the way I do coolant fills after repairs or a flush is to add a couple gallons of coolant/water mix (50/50)...start the truck with the reservoir cap off (turn heater on vent and fan speed 1) and keep adding until engine gets to operating temperature and make sure you have about half of the overflow reservoir full. shut off truck, replace coolant cap and run. check after it cools down then fill accordingly.
     
  3. mathalicka

    mathalicka GMFS Member

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    replace the coolant reservoir cap
     
  4. JimC

    JimC New Member

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    Had the exact same issue & a coolant flush did nothing. Read somewhere on a Jeep forum that the heater core can plug with "goo" over time & to flush it backwards. Tried that & haven't had a heating problem since!
     
  5. Wayne Barnes

    Wayne Barnes New Member

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    truck operates at normal temperature as it should still no heat flush backwards Flushed for words still no heat the heater core is not leaking check that still don’t know what it is
     
  6. Wayne Barnes

    Wayne Barnes New Member

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    And I did replace the Cap
     

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