[lowrydr310]

I'm not new to turbocharged cars, used to have a 4G63 mitsubishi 'back in the day' but lived in a state without emissions tests so I ran a crankcase breather filter and a catch can setup.

I had my 335i charge pipe and intercooler out for a recent AC compressor replacement and noticed a nice coating of oil inside the intake piping and inside the intercooler itself. It didn't look terrible but enough to drip out of the charge pipe when I had it off.

How much is normal? I have the RB metal PCV valve and a fairly new Elring valve cover and flapper hose, so no obvious issues with the PCV system.

[Rob@RB]

This is a fairly normal visual. I remember pulling the plumbing off my mint bone stock and easily driven 20k mile N54 and seeing similar nearly 15 years ago. All said definitely use oil loss/consumption rates as a better gauge to determine whether an abnormality exists or not, if there is an issue it will show and you can work from that vantage point.

[lowrydr310]

Originally Posted by Rob@RB

This is a fairly normal visual. I remember pulling the plumbing off my mint bone stock and easily driven 20k mile N54 and seeing similar nearly 15 years ago. All said definitely use oil loss/consumption rates as a better gauge to determine whether an abnormality exists or not, if there is an issue it will show and you can work from that vantage point.

It's 1/2 quart to 1 quart low after about 5000 miles, and I like to push it a bit after it's fully warmed up. I consider that normal given the driving conditions, so it sounds like that's normal.

With that said, would a catch can setup eliminate it? Are they easy to revert back to stock when needed?

[Rob@RB]

Originally Posted by lowrydr310

It's 1/2 quart to 1 quart low after about 5000 miles, and I like to push it a bit after it's fully warmed up. I consider that normal given the driving conditions, so it sounds like that's normal.

With that said, would a catch can setup eliminate it? Are they easy to revert back to stock when needed?

Regarding oil/loss consumption rates consider that BMW considers up to 1qt/~900miles a high threshold of "normal" for the N54 engine, so with your current oil loss/consumption rate you should be very relieved with the very small oil amount being lost during engine operation.

While the BMW high threshold is a very poor baseline in the opinion of most and a sign of something needing help; I'd still consider 1qt/2,000-3,000 miles "fair to good" and 1qt/4,000-5,000+miles being great to excellent. Ultimately it sounds like whatever you have going on with your PCV/Turbos/Engine health is going quite well at the moment and I'd not worry about any light plumbing oil coating in the slightest.

Hope this helps.

Rob