Cold Air Pushing Into Cabin 01 Tahoe

[duffus]

I have an 01 4x4 Tahoe with 94k miles purchased used a few months ago with the 5.3L engine.

 

There seems to be leak in the firewall or the "vent" for the hvac system. It is most noticeable at highway speeds (greater than 45mph) on days when it is less than 40F outside. Air is pouring into the cabin on the passenger side nearest the door.

 

The air comes in so quickly, the passenger's foot is uncomfortable. The "recirculate" button will stop this air flow, but kicks off after 15min or the defroster has to be used to keep the windshield clear. When it drops below 10F, the passenger needs a blanket over their foot. I inspected the firewall and as much as I can see with a flashlight under the dash and i can't find that is missing from the firewall.

 

Any suggestions on how to diagnose or fix this?

[C & A s Dad]

There was a post on this concerning a Burban about 2 months ago and someone posted a fix. I just cannot remeber what it was titled and cannot remember the fix. Maybe you can search it. Hope you find the post becaue it will likely answer your question.

[concours]

There is a GM Technical Service Bulletin on that... bloody JUNK vehicles.... my '94 had it, my '01 has it. Talks about sabre sawing the tin to access the heater plenum, improperly placed foam gasket, etc. The Playskool engineers should have to ride 6 hrs. in the -25F cold like my family does. There is no damned excuse for this...