Heater takes forever

Discussion in 'Chevy Truck Talk & GM News' started by evo_lution, Dec 11, 2013.

  1. evo_lution

    evo_lution New Member

    Hey guys, my '00 Silverado 1500 4.8L takes a very long time for the heater to get hot, before i leave to work I let it warm up for 10 min with the heater blasting, then I drive for another 10 before I even feel a little bit on warm air, I don't know where to start looking? Also the fan makes a lot of noise with the A/C on but not so much with the heat I don't know if this is part of the problem or a separate issue
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Welcome to GMTC! Is the coolant level full When was the last time it had a coolant flush? I can let my 05 yukon xl idle for 10 minutes and I will have luke warm air. But, within a minute or 2 of driving it is warm. I also park in a garage that never gets below 35 degrees. If it is 10 degrees out it is going to take your truck longer to warm up. Possible causes for your issue are, bad thermostat, partially plugged heater core, low coolant. I am betting on a sticking thermostat. I would change it out and flush the system while you are at it. Cost you $25 for the thermostat and gasket. (be sure to not let the guys at the parts store talk you into a "fail safe" thermostat. They tend to stay open and you will never get hot heat) By letting your truck idle with the blower full blast you actually causing your truck to take longer to heat up. You are displacing heat from your coolant with the heater core. Like another radiator. That is why when your truck over heats they say to blast the heat. It displaces heat from the cooling system faster. If you let it idle with the blower off or on low it should heat up slightly faster.
  3. evo_lution

    evo_lution New Member

    I have also tried it with no blower on and got the same results, Coolant is full, its been about a year since I've flushed it, but I only put about 1000 miles a month on it, it is parked outside usually never colder then 20°, I'll try the flush and new thermostat first and go from there, any suggestions in type of coolant and thermo? My temp gauge never goes above 180° summer or winter
  4. Guardrail

    Guardrail Member

    If your thermostat is stuck open, you will not get any heat. The thermostat is designed to trap the water in the engine block and keep it at a certain temperature. If the thermostat stays open, the water just circulates and you have about 5 gallons running around not getting hot.
  5. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    that thermostat has to be stuck open. your gauge should be just under 210 when hot
  6. evo_lution

    evo_lution New Member

    Ok. Coolant flushed, and new thermostat is in, truck is running a little below 210°, but still hardly any heat!!
  7. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    you may have air trapped in the system. how long did you let it run with the cap off after refilling it? did you turn the heater on when you flushed it? you may need to disconnect the rubber hosed going into the heater core and try to flush them out with a garden hose. Your heater core could be partially clogged.
  8. evo_lution

    evo_lution New Member

    Around 20min with cap off, I flushed it through the heater with it on, now when heater is on low I can fell the warm air, but if I turn it up, if starts coming out cool, and full blast doesn't really have much force
  9. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Under the hood, find the two pipes/hoses that provide the coolant flow to the heater core. Are both hot?

    If both are hot, you may have an air flow problem inside the truck (when you have the control knob set to floor and the blower on high, do you get lots of air flow from the vents?)

    If they, or one, is not hot, you have a water flow through the core problem.
  10. evo_lution

    evo_lution New Member

    The hose on the right gets hot but the left one isnt

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