Strip Caulk

[t5montecarlo]

The 1978 and 1986 shop manual refer to applying strip caulk to the top and sides of the AC and heater box, where it meets the firewall.

The factory sealer is extremely hard, and was could only be removed by chipping/cracking it into pieces.

There used to be a topic on this subject but it has been pruned, or is no longer indexed.

Please enlighten me about strip caulk. I want to be sure that I have no leaks after I install the heater box.

 

[melloelky]

it's 12" strips of very soft very pliable almost butyl tape like strips that is used to fill crevices/voids to keep moisture etc out of areas like around the heater box.i used a heater box gasket then pressed strip caulk around the seams and around the bolt holes before i put them in for good measure.i also used it when reassembling the box where to halves met.the factory sealer might of been lacquer based and that's why it dried up like that.it's common place on these cars.the seam sealer today is urethane based.

 

[t5montecarlo]

I am glad you chimed in, melloelky, I knew you had done this to your car.

It appears that strip caulk was originally used between the halves.

I have a new gasket.

Did you apply the caulk to either side of the gasket or did you install the gasket dry?

Did you install the box, then seal around the edges, and then remove bolts and put some caulk in the holes and retighten them?

Is there a recommended brand/part number for the strip caulk?

 

[Ed Cannon]

Its also called "dum dum" we use it a lot at the shop.

 

[melloelky]

i too used it to seal the halves.i installed the gasket dry,installed the box,pushed some around where the box meets the wall,then removed one bolt at a time and put it on the backside of the bolt head/washer and reinstalled one at a time.
the term strip caulk is what 3m calls theirs.it's #08578.i know transtar makes a version but i don't know what they call theirs or what the number is.

 

[Doober]

I used it too for mine, just made sure I cleaned both halves very well. I didn't use a gasket at the firewall.

 

[t5montecarlo]

Is 1 box of the 3M caulk sufficient?

 

[melloelky]

Is 1 box of the 3M caulk sufficient?

oh yea,four of us at work have been using one box for over a year,it goes a long way.

 

[t5montecarlo]

Its also called "dum dum" we use it a lot at the shop.

I have noticed it is used in other places, too, such as the mounts for the spoiler on my Monte Carlo.

What uses does it get at the shop?

 

[melloelky]

when i installed my heater box i put it around the backside of the bolthead and when it was tightened it would seal the underside of the bolt to the box.it would press out the access making the seal too.i see it under trunk weather stripping in spots to keep from moving,to seal hardware that goes from the outside to the inside,you might see it on the backside of your spoiler nuts its keep water from following the hardware inside,keep broken little plastic caps that snap into the door panel from falling off,help hold vapor barriers on doors,where tail lights meet the rear body panels to keep moisture out,put some around anything that's gonna pass through the firewall i wrap some around the grommets/plugs etc before i push them through.you're not gonna fill holes with it but it's cheap insurance.it's pretty handy sealer it's easy to use..