Check what i found. How is this possible...mother of god!
I plan to chip out bits and vacuum as i go.
Any suggestions how to clean this, with diesel maybe?

 

Wow
what model is this?

 

C250, year 2010 with 200,000km.

 

do you follow the recommended oil change intervals of your car? That is really bad!

 

Please tell us what time & milage between servicing, what oil you are using and how long have you owned your car , just want to make sure I don't end up with the same problem.

On a serious side, degreaser scrape off what you can and vac it up use a stiff brush and some degreaser type fluid to wash everything else mop up what you can, remove the sump plug and let what flows in the top of the engine flow out the sump plug and keep cleaning until spotless.

Let it drain overnight, install sump bung full with diesel oil warm up then quick spin around the block.

Change oil and filter refill with diesel oil, drive until oil changes colour then change oil and filter again.

 

It reminds me of this thread, so likely no oil changes:

https://mbworld.org/forums/c-class-w...50k-miles.html