water leaking in firewall, no sunroof

rockyrunner99

Veteran Member
Joined
Aug 20, 2009
Location
Grand Rapids, Mi
TDI
99.5 Golf
I have a new to me 99.5 golf. When I got it, it had a bunch of tree debris up in the cowel area. I power washed everything really well before i really realized how bad. Afterward there was water on the drivers side floor. I cleaned all the tree debris out hoping that would let it drain and fix the problem but it has not. Has anyone else had this problem? where is it coming from? thanks
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Most likely the bulkhead wiring pass through. It's not that great of a gasket, and hitting it with high pressure water probably forced water past it.
 

Blacktree

Veteran Member
Joined
Sep 9, 2015
Location
Central FL
TDI
'02 Jetta 5-spd
Been there, done that. Like mentioned above, the seal for that wiring pass-through failed. Or to be more specific, the plastic pass-through warped over time, so the seal had a gap in it. Liberal application of silicone sealant fixed the problem for me.

The pass-through is on the driver side, underneath the windshield wiper motor. See photo below.



You can test that by having someone spray the area with a garden hose while you watch from underneath the dash. Make sure the engine is off, because there is a bunch of electrical stuff right under the pass-through. You don't want to inadvertently fry something.
 

tgray

Veteran Member
Joined
Sep 12, 2004
Location
Marengo, IL
TDI
'02 Beetle, '05 Golf, 2000 Jetta, 2001 Jetta, 2002 Jetta
I found it best not to do the repair like the above photo. I have had this type of repair work for a while and then fail again later. Rather assume it is leaking there to begin with. Pull the components apart, clean everything up and caulk the actual seal (with a good grade urethane caulk only). The seal tends to harden and allow water in these cars over time. It is not that bad of a job and well worth it even if it is not the actual problem right now. It is good insurance for down the road. I have seen when it really down pours and the leaves plug up the drain the water level can get quite high in the area where the housing meets the body.
 

Blacktree

Veteran Member
Joined
Sep 9, 2015
Location
Central FL
TDI
'02 Jetta 5-spd
Pull the components apart, clean everything up and caulk the actual seal (with a good grade urethane caulk only).
Yes, I disassembled and cleaned it before caulking it up. When I reassembled it, some of the sealant oozed out. So I decided to spread it around.

I did that repair in May of 2019, and it's still good.
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
yup, after fixing all four sunroof drains in my 05' golf i still had a leak and traced it to plenum hood for the rainbow connectors. I think the weight of the wire bundle over a decade and a half caused the rear center of the cover to warp and lose seal. I unbolted mine, unplugged all the connectors, cleaned it up and applied a bead of clear permatex rtv to the sealing surface of the body, then reinstalled the cover. Another design flaw is that the actual "standpipe" is not tall enough so it doesn't take much water ingress to overflow the shallow levee.
 

tgray

Veteran Member
Joined
Sep 12, 2004
Location
Marengo, IL
TDI
'02 Beetle, '05 Golf, 2000 Jetta, 2001 Jetta, 2002 Jetta
Also when I do this repair I pull the wiper assembly out. Maybe you can do it with it in but it makes the job much easier for pulling 3 more bolts.
 

tgray

Veteran Member
Joined
Sep 12, 2004
Location
Marengo, IL
TDI
'02 Beetle, '05 Golf, 2000 Jetta, 2001 Jetta, 2002 Jetta
When you are in there examine the caulk line that runs along the firewall. If the car was ever hit, then that can crack and cause a leak as well. That kind of leak runs down the firewall and floor board and soaks the underneath of the carpet.
 

rockyrunner99

Veteran Member
Joined
Aug 20, 2009
Location
Grand Rapids, Mi
TDI
99.5 Golf
I got it fixed today. Its a 99.5 so it its a little different setup. That is definitely where it was coming in though. Took everything out and caulked it.
 
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