Outer Heater Box hot air question?
 

There is a lot of hot air coming out around the hose where it meets the outer heater box. See pic below.

Will insulating the area with some spray foam get more heat into the cab of the truck?

Re: Outer Heater Box hot air question?
 

i'd be carefull with the spray foam, you wont want to get a bunch inside. you could just silicone or caulk it . i believe there was originaly some sort of a foam seal . when replaced the cores in my trucks , i cut a small pieces of foam matting i had to squares about 2" with couple holes to put one the inlet/outlets .

Re: Outer Heater Box hot air question?
 

it might help// but if the inside of the heater box is clogged up with 40years of crap there wont b much extra flow of heat into the cab

Re: Outer Heater Box hot air question?
 

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I agree with Cliff. If you aren't getting a lot of heat out of your heater I'd be checking for debris or a mouse nest between the blower motor and the heater core... That would also cause excess air to exit around the tube.

LockDoc

Re: Outer Heater Box hot air question?
 

Sprayfoam and automobiles do not mix. As suggested [and just done to my truck after a 3 yr hibernation] clean out the heater box first then use something such as seam sealer[flexible], urethane sealer or butyl tape to seal the area around the hose. I would not recommend silicone as silicone attracts and traps moisture, remember this when considering silicone for any hole filling situations.

Re: Outer Heater Box hot air question?
 

Ok, I just gooped some Silicone around it for now...

If I don't notice any difference I'll remove the box and see what treasures I find inside! For now the heat works well, I had noticed the amount of air coming out and thought the system might be improved if I insulate...

Thanks for the tip Cheyenne Shortstep...I will note that in the future...I'd like to redo entire system in the future...

I have seen some heating/cooling systems without the outer box...any info on these? the tubes plug straight into the firewall???

Thanks again!

Re: Outer Heater Box hot air question?
 

i used this kit from Classic Parts of America (Part # 68-765) on the 67 sealed everything up nice

Re: Outer Heater Box hot air question?
 

i used the same kit as hubscrub and had great luck with it. It gave me the chance to clean and check the heater core for leaks plus reseal everything. If nothing else.... i would use the tape they use for a/c lines and fittings. That should do the trick!! Good luck!!

Re: Outer Heater Box hot air question?
 

What's the best way to get access to clean everything out? Is it better to remove the outer box in the engine compartment or take everything apart under the dash inside the cab?

Re: Outer Heater Box hot air question?
 

You have to remove the outer box. You cant get to it from inside the truck.

to do this you will need to unbolt the passenger side hood hinge and slide it forward, carefully. I think there is also a bolt that is hard to get too because of the fender. The PO of my truck had broken the heater box flange at this location, so I didnt have to fool with that bolt. If memory serves me correctly, i think you have to drop the fender to get to it.

Maybe someone else can chime in on that one. There also might be a FAQ or thread on how to remove it.

Re: Outer Heater Box hot air question?
 

You can clean 90% of it by taking the heater box off of the engine compartment side. Then just blow some compressed air through the inside passages. You have to drop the inner fender panel down to get to a couple of fasteners on the bottom of it. You can probably get them off without dropping the inner panel but I've never been able to get them back on....

LockDoc

Re: Outer Heater Box hot air question?
 

Once you pull the front cap, it's not a big problem....:lol:

But, the nuts are on the outside (firewall), which attach to studs that are part of the inner heater ducting.

Re: Outer Heater Box hot air question?
 

Great advice as usual. Thanks for the help guys!

Re: Outer Heater Box hot air question?
 

I would pull it and clean it as others suggested. Then I would place 3M Strip caulk around that hole opening. It isn't permanent so you can still swap heater cores when yours leaks.

I keep a box of it around the shop. So far in 26 years of owning vehicles I'm on my first box. It goes a long way.

I don't work for 3M

Re: Outer Heater Box hot air question?
 

On the 70 I just acquired, someone (don't know if it was factory) used a substance similar to plumber's putty to seal this area. As it was still pliable (after how long?) I used leftover PP from a kitchen project to reseal this area.