loud tapping noise.
 

I want to diagnose a loud noise and am wondering if I could take a valve cover off the engine AND start it up without spewing forth loads of oil.

Car is a 1989 560 SEL. 90K miles.

I would think oil would go everywhere - and would you know what you are looking for once inside? Probably can't go poking around with the engine running.

You could use a mechanics stethoscope as well. Regular one works "ok".

Is it clicking? Constant? If so, could be rocker arms, typical on the M117. Mine does it, but have been waiting to repair when I do the chain.

Well, let me explain. I recently replaced the cam shaft of the drivers side along with the rocker arms. The car ran like a top for about 300 miles then the tapping started. When you say "the rocker arms," what exactly do you mean? have I possible missed something???

I brought it to a MB shop, and they said they'd diagnose it for $100.00. When My wife went to pick up the car, they wanted an additional 2200 to pull the head off to further diagnose, and said that the it would be 187.00 for what they had done so far (nothing). No longer having faith in them, I now have a deadline guage for the cams, and the number two on the number 5 cylinder seems to be slightly out of spec. I put the largest sized thrust piece in, and it still shows a minus deviation. I believe that this is where the tapping is from. I am also wondering if the Hydraulic compensator might be bad, but inn does not 'give' at all when I press on it. I am also wondering if this, in and of itself, is a possible problem as it seems to be they should move a bit.

This problem is just driving me out of my mind, not quite "toaster-in-the-bathtub," but it is getting there.

Thanks in advance for reading.

Well, let me explain. I recently replaced the cam shaft of the drivers side along with the rocker arms. The car ran like a top for about 300 miles then the tapping started. When you say "the rocker arms," what exactly do you mean? have I possible missed something???

I brought it to a MB shop, and they said they'd diagnose it for $100.00. When My wife went to pick up the car, they wanted an additional 2200 to pull the head off to further diagnose, and said that the it would be 187.00 for what they had done so far (nothing). No longer having faith in them, I now have a deadline guage for the cams, and the number two on the number 5 cylinder seems to be slightly out of spec. I put the largest sized thrust piece in, and it still shows a minus deviation. I believe that this is where the tapping is from. I am also wondering if the Hydraulic compensator might be bad, but inn does not 'give' at all when I press on it. I am also wondering if this, in and of itself, is a possible problem as it seems to be they should move a bit.

This problem is just driving me out of my mind, not quite "toaster-in-the-bathtub," but it is getting there.

Thanks in advance for reading.

This had me thinking... esp the last line.
 

From an old post by Steve Brotherton, (Continental Imports
Gainesville FLBosch Master, ASE Master, L1 27 years MB technician)

"the 420/560 motor it is most likely that the problem is a rocker arm to cam issue. It can all be done without removing the head. Removing the rocker arms to view their surface would be the first step after removing the valve cover. The removal is facilitated by the special spring depressing tool.

There will be no way to see the bad part of the rocker without removal. If the cam is rough you won't need to remove them for a diagnosis but it will require a cam. MB says that cams and rockers should be done together. In the field the rockers are replaced without the cam, at least till the cam is rough.

*****Be sure the cam oil tubes are tightly mounted into the cam stands."

Thanks for your reply. I replaced the towers, shaft, and rockers, I also checked the go/no-go of the rockers and they were good to go. THe car was really running nice after the job. Looking back I thin k that maybe it was just time for one of the compensators to go bad.

To make a long story longer...I think that I may be suffering from a bad compensator. I went back a searched again with a different set of key words. I also reread my post. I have the fattest thrust piece in there, and I still have clacking. It has to be the compensator.

One other thing.....That oiler tube thing is so important, I would not be having this conversation if I had read about them crubling when they got older and clogging the cam tower oil tubes!!!