Timing chain adjuster oil leak?
 

My M127.984 engine in my 63 220SEB is pretty clean except for what appears to be an oil leak eminating from an area in the right front of the block where the timing chain adjuster is. I can't determine the exact source because the view is blocked by my air-conditioning compressor. The leak starts there, travels down to the upper ledge of the oil pan and then trails back to drop on the cross member giving the impression that the oil leak is coming from the rear of the oil pan. My question is: Is there an oil seal in the timing chain adjuster area and can it be replaced without special Mercedes tools or master mechanic procedure? I am capable of mechanical work, have a full tool box, but no special tools. My manual doesn't prescribe a procedure for this item.

Gregg,

I thought the chain tensioner was leaking on my 4.5 as I had an oily mess in the area, similar to what you describe. What I found was that the valve cover seal was leaking. Try replacing the valve cover seal and see if the mess clears up. Of course, it could be that the gasket at the tensioner failed, but I like to do the easier job first.

There is a gasket between the tensioner and block, and should only require a 13mm or 14mm socket to remove the two retaining bolts.

Chain tensioner oil leak
 

Mike, Thank you for your prompt reply. I must assume then that it must be the timing chain tension gasket, as I can see all around the valve covers rubber gasket and it is dry. Your suggesting that all I have to do is set aside the air-conditioning compressor, remove the bolts of the chain tensioner plate, replace the gasket and bolt it back up. I don't have to worry about any springs or bearings popping out when I do so? Sounds too simple but I'll place an order for the gasket and get to it. Gregg

Concur with Mike, but at least on the M130's (sort of a cousin) it is an O-ring. They dry out and leak and look like a bad front main seal.

If it's like the M130, there is a short piece of hose between the water pump and the thermostat housing that you might want to replace while you're there.

WOW, that is a really classic car !

Timing chain tensioner o-ring leak
 

Mike,
Replacing the timing chain tensioner o-ring was no easy task when you have an air-conditioning compressor to deal with! In order to access the subject I had to drain and remove the radiator, in order to remove the fan, in order to access the bolts, behind the fan pulley. attaching the compressor mount bracket. Then after removing the bracket, with the compressor still mounted, I was able to access the thermostat housing. After heavy duty prying and removing the thermostat housing I was finally able to access the two bolts fixing the chain tensioner. Took all day! I can't imagine what it would have cost for labor at a Mercedes shop? Gregg

Ah, but see how easy the tensioner was to remove, only two bolts. It's the getting to it part that is harder on some cars. Good job, let us know if the leak stops.

PS: with the upper mounted A/C, I can see the pain you had to go through. At least on the 4.5 and the 5.6 the A/C is low mounted on the left side, leaving the tensioner in the open.

I finally completed the replacement of the timing chain tensioner "O" ring. In the process of all that disassembly I noticed that the fan is made of aluminum, so I put it on my buffing machine and it shined up so nice that it looks like I have a chrome fan! Also discovered that the generator belt was about to give up the ghost so it was replaced saving the hassle later on. For others that may attempt this job, it didn't take any special tools, just a lot of labor.

Front engine oil leak
 

Sadly, after all that work to replace the tensioner "o" ring and starting the engine, I still have an oil leak at the front of the engine. It is definitely not coming from the replaced timing chain tensioner "O" ring. It is not coming from the valve cover or the crankshaft seal. It appears to be coming from behind the water pump. Nothing in the manual that I have indicates that there is an oil source into or behind the water pump. Does anyone know different? It is a very small leak but any leak bothers me!

A year or 18 months ago, there was a post on a similar leak. It was either here or on the mercedes-veterans site. The source was the indent where the water pump housing fits into the block. Apparently there is a thin spot over an oil passage there. It was really strange. I am not making this up.

I will schlep around and see what I can find.