Heater core replacement instructions?

130,000 MILES • 3.5L • V6 • 2WD • AUTOMATIC
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XAVIERD
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Hi, I like to know the step-by-step instructions and how to replace a heater core in my 2001 Oldsmobile intrigue with the diagram description if you have any
Mar 4, 2026 at 10:14 PM
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STRAILER
  • ✓Experienced Mechanic
  • 55,658 POSTS
So, this is a big job, you will need to disconnect the battery and drain the coolant out, (engine cold). Then the dashboard will need to be removed/loosened and moved upward and out of the way so you can access the HVAC plenum, also the AC system will need to be vacuumed down and well. Remove the heater hoses and AC lines, then unbolt he dash mounts and steering column mounts to help get he dash out of the way, then unbolt the HVAC plenum mounting bolts to help get at the heater code which is inside of the heater box.

This guide goes over the generic steps so you can get an idea of how the job is done

https://www.2carpros.com/articles/replace-heater-core

Transfer any seals or insulation to the new core, install the new heater core into the HVAC housing, and reinstall the cover. If you have any troubles please upload a short video or an image so I can help walk you through the repair. Check out the images (below). Ken
Mar 6, 2026 at 1:01 AM
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