1985 190e 2.3 8v-Sounds like a deisel at idle!
 

My 85 190e 2.3 runs great and is a fun car to drive, I enjoy it very much except when warmed up, The motor sounds slightly like a deisel at idle! It had a faint knocking sound. The engine runs nice and cool and has great oil pressure and pleanty of power. I do not think this noise is related to the lifters because i already know what that sounds like. I do not think it has a rod knock because the noise goes away under load or if you bring up the RPMs a little. Has anyone else had this problem? Or know what it could be?
Thanks!:)

Timing chain and chain tensioner need replacement. I replaced my tensioner yesterday and it is not as bad at initial first startup, but mine goes away once warm. If yours is always that way at idle then you need a new chain as yours sounds stretched. Which is common over time. Chains are 50 bucks.

Hey Seven we got the same car :)

I second the timing chain, but I'll also add check your valve springs. I had one break which caused some strange noises too, irregular I should add. Getting it fixed now.

xp