135i single turbo keeps leaking oil

[Dirty135]

I have a 08 135i with a doc race single top mount running a comp turbo. Stryker performance is the shop that did the install.

I keep having an oil leak issue. Coming from the turbo oil return line. I’ve taken it back to them to fix it and 200 ish miles later the issue is back. Can anybody help me resolve this issue.

 

[steve30]

I had this exact same issue with my drain line (Doc race top mount as well). The issue is the drain fitting that doc race supplies. First of all they are not barbed/bead rolled so the oil can leak through that connection. Second, and more common issue is that they for some reason do not use the same mounting bolt position as the OEM drain fitting uses. This changes the angle and causes the fitting to not seal on the block correctly. I ordered an aftermarket -10AN fitting that uses the OEM mounting position along with a 45 degree -10AN female to barbed. This solved my oil leak.

Here is a thread that dealt with the same issue: https://www.spoolstreet.com/threads/n54-single-turbo-oil-drain-line-specs.8562/