Blocking Holes in Heater Box Doors

[ftm1776]

1991 Jetta NA, no air.

Not too bad getting heater box out of this model.

Lots of opinions to block all of the holes in the diverter doors in the heater box.

I don't think they are all blocked when new.......?

I am wondering if blocking all of the holes in the metal door that controls the flow to the heater core would cause an overheat condition when closed to any air flow. I guess some air would get by, but ?

[theman53]

If it is like the A/C ones then yes, every hole is blocked. I used the foil tape for duct and smoke pipe and covered all of mine.

[burn_your_money]

Every hole should be blocked.

[bajacalal]

1991 Jetta NA, no air.

Not too bad getting heater box out of this model.

Lots of opinions to block all of the holes in the diverter doors in the heater box.

I don't think they are all blocked when new.......?

I think they are blocked with like a foam when new, and the foam breaks down over time, which I don't know if that's meant to deliberately let some air pass or if their choice of that material was for noise reasons...

Foil tape seems like a good solution, getting the old material off and the flaps completely clean sounds like the hardest part... I have to do this to my Jetta, not looking forward to it.