Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
sorry about the wait
can you describe the noise for me ?
is its a regular tapping that increases in tempo with engine speed?
if so then it could be a sticking valve lifter, as these use a small hydraulic piston to take up the valve clearances and what can happen is the small oil ways that feed the piston chamber can get clogged up
So the 1st course of action is to try an oil flush treatment complete with a new filter and fresh oil
if you don't think this is it then try removing the auxiliary drive belt and turning every pulley and ancillary ( power steering pump , alternator etc) by hand. All should turn easily (with the exception of the AC pump) with no grittyness or wobbly pulleys- If you do find a sticky pump / alternator then it should be replaced or repairedIf the engine is stone cold you can briefly run it with no belts to see if the noise changes or has gone away, this will help show if an ancillary is the issue
Hido you still need help?Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! Thank you