Heater not working properly, blows cold air

2002 OLDSMOBILE ALERO
200,000 MILES • 6 CYL • 2WD • AUTOMATIC
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TONY WOLC
  • MEMBER
  • 1 POST
Blows cold air. doesn't overheat.
Dec 11, 2019 at 8:12 AM
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JACOBANDNICKOLAS
  • CERTIFIED EXPERT
  • 110,175 POSTS
Hi,

Have you confirmed that the engine coolant is clean and full? First, take a look through this link and see if it helps.

https://www.2carpros.com/articles/car-heater-not-working

Also, I need you to check something for me. Start the engine and allow it to warm up to operating temp. While it is warming, make sure the heater control is on high heat.

Once it reaches operating temp, feel both heater core hoses under the dash at the firewall. Both should be hot. Of one is hot and the other isn't, chances are the heater core is plugged. If both are hot, then we have an issue with the heater door which is involved if it needs replaced.

I attached two pics. The first shows where the heater hoses come off the engine. The second shows where they attach to the heater core on the firewall.


Let me know what you find or if you have other questions.

Take care,
Joe
Dec 11, 2019 at 8:40 PM