C230K Supercharger lubrication

[iozero]

I have a 2002 C230K with 186,000 on the clock. I recently read in the STAR magazine about the oil that is used to lubricate the supercharger. This is not in the maintenance manual (that I can find). I also noted that MB DOC mentioned that the oil level in the supercharger needed to be checked every 50,000 miles. I have two questions:

1) How do you check the lubricant level in the supercharger and
2) Do you ever need to change the oil level in the supercharger

My car makes a growling noise sometimes on start up that goes away after about 30 seconds of running and I have a fear that this is supercharger related.

Any assistance/advice or insight would be appreciated.