NO Heat and even colder air on deforst

Asked by dreiss Dec 20, 2013 at 02:52 PM about the 2002 GMC Sonoma SL 2WD

Question type: Maintenance & Repair

I have cool air coming out in heater mode.  I have already flush the radiator and also cleaned the heater cores.  What else can be causing this?

1 Answer

69,055

Stuck thermostat, air pocket, how did you test the heater core? Defrost blows cooler because the defrost uses the air conditioning to remove moisture from the air to defog the window quicker. Check the heater core lines for heat in both lines once the engine is up to temp. oif they are both pretty warm it could be the temp blend door isn't getting vacuum to it to open. If one line is hot and the other is cold then you have a blockage, if the engine is hot and both are cold then that's a serious blockage.

10 people found this helpful.

Your Answer:

CarGurus Experts

  • #1
    parkle
    Reputation
    1,090
  • #2
    Mike Bonnell
    Reputation
    660
  • #3
    James Mayfield
    Reputation
    410
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet S-10
2 listings
Used Ford F-150
325 Great Deals out of 13,693 listings starting at $3,800
Used Toyota Tacoma
37 Great Deals out of 728 listings starting at $9,975
Used Chevrolet Silverado 1500
200 Great Deals out of 8,052 listings starting at $1,500
Used Ford Ranger
22 Great Deals out of 701 listings starting at $8,800

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.