2008 KW W900l

The cats of that era push a lot of crap into the air dryer. Cat says it's normal , I say bull. They will not do anything to fix it. I've had a couple of major battles with cat over this.

It's one of the many problems of the SDP engines.

Keep up on the air dryer maintenance , is about all you can do. I put on a new cartridge every 6 months.

 

Billerd,you just have some extra info in your last post.
This does influence my opinion and how i would approach this.

So here's my revised plan.
Unscrew the airdryer cartridge
The airdryer has an intake which comes from the compressor.
That can (most likely will be) have grey gook(muck,dirt,.....) in it.
If it is a little then your ok,if it is full then you are in trouble.
Then there is the outgoing part off the airdryer.
That has to be 100% dry and clean.
If it isn't ,then for now put a new cartridge.


As to whether or not they put a new compressor doesn't matter,it is what you are getting or not getting in your airlines now which matters.