Heater box seals and Heater Core replacement
Thread Starter
Burning Brakes
Joined: Nov 2002
Posts: 952
Likes: 44
From: NC
Heater box seals and Heater Core replacement
I am about to reinstall my heater core and heater box on my 73 small block air conditioned coupe.
My question is, what did yall do to your heater box in order to seal it well? I bought the kit but im wondering if those foam seals are going to do their job. Im also wondering if I should put the strip caulk on top of all the foam seals.
I only want to do this job once!
Thanks for the input.
James
My question is, what did yall do to your heater box in order to seal it well? I bought the kit but im wondering if those foam seals are going to do their job. Im also wondering if I should put the strip caulk on top of all the foam seals.
I only want to do this job once!
Thanks for the input.
James
Le Mans Master
Joined: Apr 2005
Posts: 6,339
Likes: 416
From: Seattle Area WA
If it/s a quality seal kit the foam should be fine as is. Make sure your new heater core sits in the cradle correctly as you clap it down. The crappy aftermarket one I got did not and I had to silver solder it after it broke.
http://blog.scottsvettetalk.com/2007...eater-box.aspx
http://blog.scottsvettetalk.com/2007...eater-box.aspx
Racer
Joined: Jul 2004
Posts: 286
Likes: 1
From: Mesa az
I'm in the process of replacing my heater core too, and have the same concerns about the seals in the "kit" ($50+) I purchased. The distribution box-to-firewall seal is a flimsy foam that in no way replaces the original firewall insulator rubber seal. My firewall insulator was mostly missing so I'm going to make one using material I get from a heating/AC home center. Also, if your '73 is like my '69, the center divider that separates the air duct from the heater water tubes require the "tar strips". I purchased more of the "tar strips" from an auto parts store. I also used them for resealing the fan motor to case. I'd suggest comparing the old seals with the new ones and only use if the materials look similar. As you said, you only want to do this once in a life time.
Racer
Joined: Jul 2004
Posts: 286
Likes: 1
From: Mesa az
Here's the list of seals I'm going to use/replace.
HEATER/AC SEALS
Fan Motor to outer case (engine compartment) - soft tar 1/8” bead
Inner case to firewall – 1/8” thick firm rubber seal around the perimeter, 1/8” bead soft tar in center divider between air duct and hot water tubes.
Case to case pieces both inside and engine compartment – 1/8” soft tar bead
Core to aluminum frame – 1/8” soft tar bead
Aluminum frame to inside case – 1/8” soft tar bead
Core tubes to aluminum frame opening – Soft foam piece
Core tubes to car body – firm foam rubber seal with holes for tubes
Inner flapper door hinge end – soft foam rubber
Case outlet to air ducts – firm rubber foam
Air duct to air duct – firm felt
Moveable Air vents – felt
Vacuum Actuator seals – test and replace actuator if bad
Air doors seals – inspect and replace as needed
HEATER/AC SEALS
Fan Motor to outer case (engine compartment) - soft tar 1/8” bead
Inner case to firewall – 1/8” thick firm rubber seal around the perimeter, 1/8” bead soft tar in center divider between air duct and hot water tubes.
Case to case pieces both inside and engine compartment – 1/8” soft tar bead
Core to aluminum frame – 1/8” soft tar bead
Aluminum frame to inside case – 1/8” soft tar bead
Core tubes to aluminum frame opening – Soft foam piece
Core tubes to car body – firm foam rubber seal with holes for tubes
Inner flapper door hinge end – soft foam rubber
Case outlet to air ducts – firm rubber foam
Air duct to air duct – firm felt
Moveable Air vents – felt
Vacuum Actuator seals – test and replace actuator if bad
Air doors seals – inspect and replace as needed
Instructor
Joined: Aug 2015
Posts: 187
Likes: 15
From: New York
I'm working on the seal kit right now for my '72 w/AC and I'm about to lose it because the directions that came with the kit are COMPLETELY USELESS. Does anyone have pictures of how they installed all their seals? I'm only working on the heater core and box. I'm not touching the box in the engine bay.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
The original product used to seal the housing was a gray putty-like material. IIRC, last time I tackled this particular chore the dealer's parts department had it.
Le Mans Master
Joined: Mar 2001
Posts: 5,738
Likes: 644
From: Lincoln, CA
I use this Rope Caulk for many car seals.
Works great, a little sticky.
http://acehardwaremaldives.com/produ...cooling/54924/
Works great, a little sticky.
http://acehardwaremaldives.com/produ...cooling/54924/
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Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,027
You can still buy the non hardening gray stuff. Go to an electrical wholesale house and ask for duct seal. Same stuff.
