On my way to work this morning, as I left from a 4 way stop, I heard this horrible knocking noise. It can not really be heard at idle, it starts at about 1200 rpms. I limped it home and tried to make sure that it was not as simple as an exhuast manifold leak, I pulled the valve cover off and and ran it up for a couple of seconds. It sounds to me that it is coming from Cylinder #1 (furthest front - new to mercedes not sure what order). Is there a typical problem with the 85 300SD engine that I should look to? I am looking for a manual and figure on pulling the head off and starting with a possible valve problem.

Also has anyone downloaded any of the workshop manuals from www.workshopmanuals.co.uk ? This is the only one I have been able to find and it is downloadable.

Thanks for the help.