After my 2010 C300 indicated level B5 service was needed (54,000 miles) , spoke to 2 mechanics. One said that in addition to the basic stuff like an oil change, I also needed spark plugs replaced (extra charge) and transmission service (extra $380). The other mechanic said this was not true; neither of these are needed now . Which one is right?

Check the service manual for your car... You can access it on MBUsa.com...

The only definitive source as to what is needed when is MB since they made the car...

Thank you so much...had already done that. Perhaps someone else has some useful info.

Personally, I would stay 1 more year with spark plugs and do tranny fluid if it was never done previously.

Thx so much...that was very helpful. Hopefully, I can go back to the service records to see if the transmission fluid was drained by the previous owner.

I am also up for a B5 service which is done at 60K miles. If you look on page 33 of the Maintenance Manual toward the bottom it states that the spark plug need to be changed. You also need an oil and filter change, brake fluid change, dust filter and there are a bunch of things to check like brake pad thickness, etc.

Nelson