Firewall Leak.

[kygaca]

So I found out that some water gets in my car on the passenger side, and I would think this is because the firewall isn't sealed. It isn't coolant, so I know the heater core is fine. I think my best bet is to just reseal the AC and heater box with some silicone. Has anyone else had this problem? Can water enter from the edges of the box if not properly sealed?

 

[565bbchevy]

My guess would be your drain on the bottom of the ac/heater case is clogged with debris

 

[81Regal]

There is normally 3 common areas that leak on these cars. The drain as mentioned above, the seam sealer around the box, and the front edge of the door glass. Possible that the windshield could leak also. Do not use silicone to reseal the box, get some rope caulk from a parts store.

 

[pagrunt]

Common leaks problems are the as stated blocked drain of the heater box causing it to fill & drain into the car, the sealing point of the box & firewall due to seal failure or rust out, base of the windshield rusting out due to debris build up, A pillars with same issues as the whindshield base.

 

[kygaca]

Wasn't sure where the drain plugs were but I vacuumed in the box, and sealed it back up with something I got a while back which I sealed my AC box on my cutlass with. It is like a putty. Put it on the outer edges too where it attaches to the firewall. I will spray test tomorrow. Thanks for your replies!

 

[pagrunt]

The drain is in the engine compartmenton the bottom of the fiberglass/plastic case. It'll be a rubber door.

 

[83GWAGON]

Bumping this thread because I have the exact same problem with the 83 4dr Wagon I just bought. The guy I bought it from kept it in a garage but I don't have that luxury at the moment . It has been raining here for 2 days solid and I found some water dripping in the passenger floorboard , the A pillar passenger side at the bottom and the the front of the passenger front door seems to be leaking a bit.

I guess I just need to re-seal the heater box, windshield and the doors? What about the firerwall seal?

 

[mikester]

Bumping this thread because I have the exact same problem with the 83 4dr Wagon I just bought. The guy I bought it from kept it in a garage but I don't have that luxury at the moment . It has been raining here for 2 days solid and I found some water dripping in the passenger floorboard , the A pillar passenger side at the bottom and the the front of the passenger front door seems to be leaking a bit.

I guess I just need to re-seal the heater box, windshield and the doors? What about the firerwall seal?

I just had to redo some stuff on my AC box in my wagon. Did it a while ago but I realized I didnt have everything right so I ripped it all apart again.
You can buy a new box to firewall gasket from Mikes Montes. Theyre not that expensive. Downside it takes a little work to replace it.

 

[gnvair]

I would get some 3M Strip caulk. Silicone is good for rusting sheet metal steel. Plus the strip caulk makes removal easy if you every have to replace the heater core or evaporator.

 

[83GWAGON]

I would get some 3M Strip caulk. Silicone is good for rusting sheet metal steel. Plus the strip caulk makes removal easy if you every have to replace the heater core or evaporator.

Thanks for the tip gnvair. What do you think about Butyl rope/rubber as a sealer?