suburban has cold air leaking into cab from outside when driving

[k9a9f9]

I have a 2001 suburban and when it is cold outside and I drive down the road I have cold air coming into the passengers foot area. I have two friends with the same problem. Where is this cold air coming from? No the air is not on, because it is below 40 degrees when this happens.

[sub006]

Even when everything on the dash climate controls is turned off, the system lets a little fresh air in at all times. I think this is done to help keep vehicle occupants alert, awake and alive in the event of an exhaust leak into the cabin.

I once had this problem when I had my Sub's heater temporarily disconnected and had to make a lengthy trip in cold weather. I turned everything off and closed the dash vents, but cold air was still coming through the foot-level vents under the dash, above the trans tunnel! The higher your speed, the greater the volume of outside-temp air coming in.

There are no shutters to close these vents, so I ended up using duct tape! But under normal conditions, just set your heater controls for warm air at floor level and you should be fine.

[FCDGMC]

Forgive the potentially silly answer, but is your temp setting in the warm when this is happening? I find that (similar to Sub006's response) this "bleed" air that comes in even when the fan is off, is usually representative of what the temperature setting was on when the climate control was last used.

[sdwiz]

I have a 2002 tahoe with the same problem. Took it to the dealership and they said I had a bad gasket around the door. That was hard to believe. The Tahoe was still in warranty at that time but this item was not covered by warranty. Dealership wanted $125 to replace the gasket which they said would fix the air leak. No matter how warm I have the heater and no matter what position the heater air flow was in there was still cold air coming in. Did not let the them replace the gasket so not sure if that is what is wrong or not.

[sub006]

1. When I suggested you set the heater temperature lever to the warmth desired, I neglected to specifically mention that the heater must also be on (vent/ac/defrost lever must be in the "heat" position) or the incoming air will not be directed over the heater core.

2. If you think you have door gasket trouble, you should have a loud, almost roaring sound at freeway speeds.

3. I once had wind noise plus a driver's door window frame that was vibrating in and out from the body jamb. Turned out to be a separated door skin at the leading edge near the upper hinge. My truck was 14 years old at the time. Junkyard doors were in worse shape than mine, genuine GM was astronomically priced and new Asian "replacements" did not fit well. The solution was to remove, dissassemble and re-weld the door skin. A couple hundred bucks, but it functions like new!

[drchemistry]

Originally Posted by k9a9f9

I have a 2001 suburban and when it is cold outside and I drive down the road I have cold air coming into the passengers foot area. I have two friends with the same problem. Where is this cold air coming from? No the air is not on, because it is below 40 degrees when this happens.

I have the same problem on my 01 Suburban! I removed the glove box so I could see into the heater area and discovered an open-cell foam seal between the heater and the metal cab air plenum. This is where air comes into the heater ductwork from the inlet around the wiper blades. This ~3/4" foam seal was leaking so much cold air through that my wife's feet would get cold even with the heater running. I carefully reached in and stuck pieces of closed cell foam tape over it and this solved the problem! I think you could also access the seal from above by opening up the air inlet grill behind the hood and prying off a snap-down cover, but I haven't tried this.

[ourgangmn]

How did you get your hand up in the area behind the glove box? I have the exact same problem of cold air entering the cabin near the passenger's feet, but I can barely see in there if I remove the glove box. All I can see is a small portion of the open cell gasket along the top edge of the heater box.