FIX - Oil leak at DSG mechatronics connector

[dundahead]

Just wanted to share a fix I came up with for a leak I had at the DSG mechatronic plug — specifically from the small vent pinhole that. I know a few others have run into this issue, so hopefully this helps someone.

The leak was slow but persistent, and after some inspection, I found it was coming right from that tiny vent hole. I verified this by adding air into the system from the vent at the top of the transmission. Rather than replacing the mech unit, I tried a simple solution that’s held up surprisingly well.

Here’s what I did:

• I used 1/16" thick rubber from a pack of plumbing gasket sheets (you can get these at most hardware stores).
• Cut a small circle that fit neatly inside the circular recess of the mechatronics plastic — basically around the pinhole.
• Placed the rubber piece over the pinhole and reinstalled the plug. The pressure of the plug itself holds the gasket in place.

I've put about 30,000 miles over two years on the car since doing this, and the leak hasn’t returned. No error codes or shifting issues either.

I know this might not be the "official" fix, but it worked well for me, and it’s a quick, inexpensive option for those dealing with the same issue.

Let me know if anyone has questions or has tried a similar approach!

 

[gerz98]

Hi mate. Interesting. This was my original photo - i still never got around to fixing it. Apparently you need to replace the 2 pressure sensors. Im tempted to try this but surely they breather hole serves a purpose???

 

[dundahead]

Hey @gerz98 Sorry for snagging your photo—it's the best one I could find! I never really dug deep enough to consider the pressure sensors. I just assumed the mechatronics unit needed to be replaced after reading a few threads where others mentioned that.

Did you have any codes along with your leak? And are those sensors actually part of the mech unit? I was wondering the same thing about that little hole—it looks like a vent, but there’s a main vent at the top, so who knows. Maybe its some sort of post that something behind it aligns with? Honestly, I just wanted the leak to stop and wasn’t ready to shell out for a new mech unit.

 

[gerz98]

No need to apologize hahaha. Just wasnt expecting to see my photo! So there are 2 pressure sensors. There have a gasket each which when fails will leak fluid from the valve body into the TCU. Over time the fluid will degrade the circuitry in the TCU. You can replace them but it's not the easiest task. There's a few videos on YouTube. I have no fault codes. Car drives normal.

 

[gerz98]

Hey @gerz98 Sorry for snagging your photo—it's the best one I could find! I never really dug deep enough to consider the pressure sensors. I just assumed the mechatronics unit needed to be replaced after reading a few threads where others mentioned that.

Did you have any codes along with your leak? And are those sensors actually part of the mech unit? I was wondering the same thing about that little hole—it looks like a vent, but there’s a main vent at the top, so who knows. Maybe its some sort of post that something behind it aligns with? Honestly, I just wanted the leak to stop and wasn’t ready to shell out for a new mech unit.

So I bought some rubber today. How on earth did you cut it to size and fit/position is in place?