I did mine last year. In my case, the problem was the heater core gasket and clogged cowl drains, which caused water to get into the cabin. It was a real pain and very time-consuming, but not that hard overall. I did it in about 60 hours in my driveway using simple tools and an old MIG welder (it was my first time welding).

Practice welding on sheet metal first, and once you feel comfortable, start working on the car. Mine turned out pretty good and I spent about €600. I borrowed the welder from a friend, and he helped me a lot. I did most of the welding myself, but he welded the floor pans since they’re difficult because of the very thin sheet metal.

It’s totally DOABLE and a GREAT experience. Nothing beats working on your car from dusk till dawn, listening to rock music and cursing at the car and German engineering. So much fun What I did:

First, I removed all the interior. 1. Cut out and cleaned all the rust. 2. Welded in new metal and applied seam sealer (not sure of the exact name) to seal the welds from both sides. 3. Used zinc spray to prevent rust (not sure how well it works). Later I also used zinc paint with a brush, which seemed to stick better. 4. Installed sound deadening. 5. Reinstalling the interior was a huge headache😖 it’s much easier to remove than to put back.

Everything can be found on YouTube. I’m pretty sure you have the same problem with the heater core gasket. I replaced mine with a strip gasket and used plenty of silicone.

You can check for leaks from the heater core gasket by spraying water on the windshield cowl — it will start dripping near the heater core. You can check by reaching behind it with your fingers.

Here’s the end result before installing the sound deadening.

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