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To select your genuine parts, look at the mercedes parts catalog with engine diagrams.
This will ensure you get the correct parts numbers for your engine.
Last edited by CaliBenzDriver; Mar 26, 2026 at 05:35 PM.
A 270 050 01 22 I think this is the part, based on my VIN. Just wanted to confirm that roller tapet is what I am looking for
Originally Posted by CaliBenzDriver
To select your genuine parts, look at the mercedes parts catalog with engine diagrams.
This will ensure you get the correct parts numbers for your engine.
yes exactly item No40 is the roller bearing pump + seal + roller
now you have trusted P/N you know match your engine.
Just that it can be the pump itself too.
The pump piston returns by a spring force and the spring can get weak over time. This means there may be a gap between the roller and the cam shaft lobes that the make more than usual noice.
I had this and the rattle was quite bad on my S550 and to make sure I fix it I changed both fuel pumps with rollers.
Problem was fixed with all new parts but I don’t know which part it was that needed fixing. Would have possibly taken even four tries to change just one part at a time on the two pumps so I just did them all on one try.
But the tapping noise is normal for these motors with the cam driven HPFP so replacing the pump and the roller follower may not fix the noise issue, but as previous posts say it may just be a good preventive maintenance move to replace them anyway.
I experienced something similar on my C43 after new spark plugs, but turned out to be a dying belt tensioner making a similar whining noise. Made me wonder if the plug change was the culprit but it was just a cheap tensioner giving up.
