Blend door heater blows cold air?

Tiny
BMCMURTREY
  • MEMBER
  • 2008 BUICK LA CROSSE
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 108,000 MILES
Heater blows cold air. Both hoses are hot, so there is coolant flow.
Tuesday, November 25th, 2025 AT 6:28 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I would make sure the coolant level is full, (engine cold only). Even though you feel coolant (hot) the flow rate can be low because of a clogged heater core, you might want to remove the hoses and flush it using a garden hose. I don't think it is a blend door actuator because both sides (right and left) would need to be bad at the same time. This does have dual range climate control correct?

Here is a video to help

https://www.youtube.com/watch?v=SNRb6pSwYuU

Please upload a short video in your response of the problem, so I can see what's going on :)
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Wednesday, November 26th, 2025 AT 10:52 AM

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