Hi All

This is my first post, I own a Mercedes C220 CDI (diesel) 2002 classic I have had an oil and filter change done about 6 weeks ago and I am sure the engine sounds more noisey since then? (Sounded better with dirty oil) The oil used was 5w/40 grade fully synthetic
My question is what is your recommendations be to use fully synthetic or part or mineral oil and what grade and is there anything to be concerned about

Thanks in advance bluepassat

 

I do all my oil changes and use castrol 10w 40 in my 84 300d turbo. works fine and is if anything quieter.