Hi all,

Went for a long ride this weekend in my 74 2.0 without running the AC

Even with red knob on floor in off position, I noticed a god bit of heat coming from driver's side foot well. Passenger side seemed ok.

I put it on lift when I got home. The flap at the heat exchanger seems to be in closed position. I pulled hose to confirm. I did loosen up on cable just to be sure but have not driven since. It does feel like there may have been some kind of foam on the flapper which is long crumbled but not certain about that.

Anything I should check. I do have stainless heat exchangers.

Thanks.

IIRC the flappers had some sort of cork or other material (the stuff that crumbled off) to help seal it when it's closed. Sounds like your driver's side isn't sealing as that's the only way for the heat to get into the cabin. Make sure the cable has enough slack such that it allows the flapper to completely close. If that's still allowing heat in, it looks like 914 rubber sells replacement foam material:

https://914rubber.com/flapper-valve-seals-i...lower-housing-1

I had the same in my car. Heat at my feet until I was able to have the flapper close all the way.

That's the replacement foam gasket for the fresh air intake box under the cowl and is unrelated to heater control boxes under the car.

That's the check I would recommend. Did you run the car with the cable loose and the hose off? Did heat come out? Either the cable is out of adjustment or your heater control box has bad innards.

Make sure that the tube that holds the flapper valve is not shoved up too far.

Had a situation where the tube was holding the flapper valve open.

@Amphicar770

Went for a long ride this weekend in my 74 2.0 without running the AC

Even with red knob on floor in off position, I noticed a god bit of heat coming from driver's side foot well. Passenger side seemed ok.

I put it on lift when I got home. The flap at the heat exchanger seems to be in closed position. I pulled hose to confirm. I did loosen up on cable just to be sure but have not driven since. It does feel like there may have been some kind of foam on the flapper which is long crumbled but not certain about that.

Anything I should check. I do have stainless heat exchangers.

Thanks.
[/quote]

The flapper is probably not closing all the way from rust in the seal of the flap.
I have restored many flappers and the seal is a combination of metal screen and what looks like asbestos.
Remove the flapper from the car. Wear a mask and dig out all of the old seal. I use needle nose pliers to pull the meal screen from under the crimped edge. Then I use a wire brush in a cordless drill to remove most of the rust. Then soak in Evaporust for a day or two.
The seal is not needed. The Dansk replacements do not have them.The metal to metal contact is enough to block the air flow. There are also springs in between the two flaps that apply pressure. Check that they are not broken.
Or replace the valve with a good used or new one. I have some it you are interested.

@rjames
IIRC the flappers had some sort of cork or other material (the stuff that crumbled off) to help seal it when it's closed. Sounds like your driver's side isn't sealing as that's the only way for the heat to get into the cabin. Make sure the cable has enough slack such that it allows the flapper to completely close. If that's still allowing heat in, it looks like 914 rubber sells replacement foam material:

https://914rubber.com/flapper-valve-seals-i...lower-housing-1
[/quote]

That seal is for the front blower motor and is not the correct material (foam) to hold up to the heat in the flapper. No seals are needed in the flappers. The Dansk replacements don't use seals.

Until You sort it out, change the dash control settings to the defrost position and the temp lever to mix with outside air. It will still be warm but the heat gun hot air won't blowing into the footwell cooking your feet.

Thanks all. I did loosen the cable up a bit so will see what happens on my next trip. They seemed to be in closed position but that cable is slightly tauter than the passenger side so perhaps in motion it was partly opening.

I previously removed whatever was left of the crumbling old foam / asbestos when I had the engine out.

I do not think it is a rust issue. The units are pretty clean and move pretty freely. My 914 is remarkably free of rust with original paint! (of course you will find some if you look hard enough but overall in superb condition).

Thanks.

Mike

[quote name='bdstone914' date='Aug 25 2020, 07:04 AM' post='2845786']
@rjames
IIRC the flappers had some sort of cork or other material (the stuff that crumbled off) to help seal it when it's closed. Sounds like your driver's side isn't sealing as that's the only way for the heat to get into the cabin. Make sure the cable has enough slack such that it allows the flapper to completely close. If that's still allowing heat in, it looks like 914 rubber sells replacement foam material:

https://914rubber.com/flapper-valve-seals-i...lower-housing-1
[/quote]

That seal is for the front blower motor and is not the correct material (foam) to hold up to the heat in the flapper. No seals are needed in the flappers. The Dansk replacements don't use seals.
[/quote]

Thanks for the correction. That'll teach me to try and respond to something after midnight when I'm tired and should be in bed.

Any harm in just capping them where the hoses attach. I only drive her in the nice, warm weather months and it is easy to reattach the hose if needed.

@Amphicar770
' date='Aug 25 2020, 12:48 PM' post='2845858']
Any harm in just capping them where the hoses attach. I only drive her in the nice, warm weather months and it is easy to reattach the hose if needed.
[/quote]


You can cap off the hole to the long.
Pull the flex hose. Or just pull off the flapper and hose and leave the heat exchanger open. Critters like to make nests in the longs.
You probably need to scrap the seal out of the flapper.

Just to close this out. Loosened the cable at the flapper by a fraction of an inch. Problem solved. Thanks.

Good on you! A lot of threads never get closure and knowing the solution is the most helpful post of the whole thread.