Official fix for water ingress from tail lights.

[MJ-IOM]

Hello
Please feel free to delete and show me the original thread but what is the best fix for leaking rear light units into boot floor? I’ve had to us silicone sealer for now but intend to fix properly when the weather gets better. Basically what would a body shop do if it was taken to them?? Is there an official fix by Vw or is it silicone sealer and hope for best? I discovered a lake this morning help.

[Ripstop]

I had to fix this recently and in the end it was the rear boot vent. However there are 2 possibilities. The first is that it leaks where the compressible foam gasket around the cable connection point on the light unit seals on the bodywork. I basically cleaned the body panel around the square hole in the body and the soft foam gasket itself. Then I dried it out as best as possible and used a tiny smear of silicone grease on gasket, press fitted the light unit as a test and removed. I verified that a very thin layer of grease marked the body panel to show it was sealing.  You really need to remove the carpet inside while you tip water down the boot rain channel and check for water ingress with a torch.

The second more challenging area of leakage is the boot vents. Grime can build up on the upper horizontal side of the vent and eventually cause a leak. This happened to me and it was a rear bumper off job. I could see water ingress around the seal from inside the car. Same cleaning procedure and the tinniest of smears of silicone grease and a new vent.

You can also get this if the inner body panel is slightly bent preventing the boot vent from sealing flush. That comes from bumber ding usually as it makes the metal vent hole slightly uneven. Doesn't take much.

[vwdubster77]

As above.

My spare wheel well was like a swimming pool, had to take the bungs out to drain it. Initially I found water was coming in from the OSR light seal. For the volume of water in the wheel well I wasn't convinced this was the source.

I replaced both rear light seals, had the bumper off, wasn't impressed by the state of the vent seals, replaced both of these also.

Still found water was coming in, in the end most of the water ingress was from the tailgate boot seal, re-sealed this.

Not leaked since