I am replacing the foam insulation on my HVAC blend doors. Is the hole in the "diverter door" supposed to be uncovered? My insulation was all gone when I opened the heater box to replace the heater core. So I'm not sure if I should keep the hole uncovered or is it ok to cover. I hate to do all of this work and have it whistle because the hole should be there and I cover it. The first picture is the diverter door in the car with the hole. The other pictures are the blend doors out of the car and covered with new foam. I covered the hole in the blend doors.

 

It's hard to tell which door that is.

If it's the recirculate/fresh-air door, as it appears to be, then it's to keep at least SOME outside air coming in, even when set to recirc. (max air)

Also, when you have the system set to max air, if you then try to switch it to normal air with max blower, the vacuum created against that door by the blower may make it impossible for the vacuum motor (diaphragm) to overcome it and move the door.

 

Wow!

You explained that perfectly.

I should not be surprised, I have seen a good number of great Post from you.

 

Thanks vorteciroc, I'm only a hobbyist but with mfg experience, I can only try to pass along what I've seen and what I've learned, in a way that helps others to UNDERSTAND (as opposed to "look up in book") what's going on. Sometimes common sense goes a long way. Other times, a trip to a vehicle assy plant such as Bowling Green can light the light bulbs inside the brain. I've never worked for GM, but I hope I at least understand some of what their people were thinking at the time; even if it seems stupid to us out here sometimes, all these years later. There is (was) definitely madness to their method.

 

I'm not sure what happened, but I thanked you and then added that it is the Heater/Defrost door. I have no idea why it did show up. Also, I added the picture from my service manual. Oh well.

So it's the Heater/Defrost door. I saw a picture of the Heater/Defrost door on the "for sale" section and it was from a Camaro which is slightly different. It was hard to see, but it had the original foam insolation and there was a square hole, but I couldn't tell if it went all the way through.

 

That actually was pretty darn impressive, Sofa. I had no clue!

jster1963, what kind of foam is that and where did you buy it? And what kind of adhesive did you use? Looks professional.

 

QwkTrip Thank you very much! This is and adhesive backed foam I bought at a crafts store. I think it was Joann Fabrics or Hobby Lobby. Even though it's adhesive backed, I also used contact cement on the metal first. I tested 3 ways before I went with the contact cement. I used just the adhesive foam without prep. I then used the adhesive foam and alcohol cleaning of the metal. Then I used contact cement on alcohol prepped metal. The alcohol prep and contact cement along with the adhesive foam was a total winner. I had to wire wheel it off! Here are some pictures of the service manual and the foam. This is not the same density foam as the original, but I think it will work. I wanted original foam, but I couldn't find it.

 

I'll bet whoever made that label doesn't have a 3 year old. You'd have that stuff stuck to the cat and walls all over the house.

 

LOL! Tru dat ;-)