crestwooddan

I have an '87 300 Turbo Deisel with 235k miles. There is a knocking noise coming from the front third of the head, as determined by the iron rod to the ear stethescope technique. The noise is not present down in the block and it starts after the engine has warmed up for about a minute. I think I have a lifter that is stuck so it doesn't take up the valve lash. Otherwise the engine runs fine.
The MB parts man says it is very rare for the lifters to fail.

Does anyone have any ideas on other noise sources, maybe injectors, and how to differentiate.

Also, to remove the cam shaft, to get to the lifters, the MB manual says to take out the oil pump, which is a huge job. Does anyone know if there is a work around
cheers

Untertürkheim

Lifters rarely fail completely...they usually go bad from debris or varnish buildup. What type of oil do you use and how often do you change it?

Depending on your answer, I may be able to tell you how I cured the problem.

crestwooddan

I use Rotella, multi-viscosity as appropriate for the season, and have been changing it every 3 to 4 thousand miles. I did have the valve cover off and the area underneath was amazingly clean. There was no gunk in any of the low spots.
thanks

Untertürkheim

It could also be a bad injector, but the sound would be very different from that of a lifter/valve issue. Perhaps it is a bent valve?