HOT Air through Driver side foot and dash vents.

[aread]

Earlier this week I took my '88 out for a nice drive. I've known the AC has been due for a recharge, so I wasn't expecting crazy cool temps in the cabin, but after 20 minutes or so into the drive, I noticed that the foot vent and the far left dash vent were blowing HOT (really hot) air, but only at highway speed. My first thought was that the drivers side flapper box under the car was stuck closed, forcing air from the HE's into the cabin. Nope, those are working as they should and both sides were fully open.

Important details to note:

1. the hot air is blowing only through to outlets, the drivers side foot vent, directly under the steering wheel and the dash vent to the left of the ignition.
2. This only occurs at high speeds >60mph
3. This only occurs when engine is warm (obviously)

My first thought is that there must be a vent somewhere that is forced open with the added air flow that occurs at higher engine speeds. IDK

Any thoughts where I should look next?

Thanks

Alex

[DRACO A5OG]

How did you check the flappers, with a helper or by yourself.

Strange, if fully closed it should be sealed. Do you have auto heat or standard heater control?

[aread]

Originally Posted by DRACO A5OG

How did you check the flappers, with a helper or by yourself.

Strange, if fully closed it should be sealed. Do you have auto heat or standard heater control?

Draco, I didn't have a helper handy, but I was going back and forth between the cabin and under the car using the red levers to test, and it seemed to work as it should. I do have the automatic heat which has stayed in the off position.

[Jonny H]

Seal has perished in the flapper box and/or the spring isn't fully closing it. Only takes a tiny gap to get hot air through.

[RSBob]

+1. Had the same issue. Perished Seal.

[aread]

Originally Posted by Jonny H

Seal has perished in the flapper box and/or the spring isn't fully closing it. Only takes a tiny gap to get hot air through.

Thanks for the help guys. I'll add that to the grocery list...