Where to put sealant on M103 lower timing cover - PeachParts Mercedes-Benz Forum

apr34 · #1 12-26-2014, 11:05 PM

I'm working on sealing the lower timing cover on an M103 and I was wondering if you're supposed to put sealant around the hole that goes through to the chain tensioner, I saw a picture of someone online that did not seal this area and I've been unable to find any information on it.
It looks to me like this hole is used to pressurize the back side of the chain tensioner with oil and I figured it should be sealed but I haven't seen anything that said definitively whether it should have sealant around it.

I'll try to attach a picture of what I'm talking about

ps2cho · #2 12-28-2014, 11:47 PM

I cant remember exactly, but I don't believe I did on mine.

If you damaged the oil pan gasket upon removal, use the same sealant and it should hold btw. Use Genuine MB gasket sealant.

If this helps with the rest of the process:
http://w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/Engine/103/01-2100.pdf

apr34 · #3 12-29-2014, 12:03 AM

I ended up putting sealant around that area just in case it was necessary, I didn't really see it making a difference whether it was sealed or not.

As far as the oil pan gasket, I just cut a section out of a new gasket and put sealant in the corners, hopefully I won't experience any leaks. I guess I'll find out eventually...

ps2cho · #4 12-29-2014, 10:41 AM

I did my lower timing cover at 112k and currently at 156k and no drips using that sealant. You should be good.

Hit Man X · #5 12-29-2014, 10:37 PM

Mine is leaking at lower left beside alternator. Any tips or 'gotcha' while in there? I did order a new oil pan gasket as I will probably need it.

I am going to go ahead and replace the timing chain tensioner arm and guide rails while in there due to the fact I am over 300k now.

apr34 · #6 12-29-2014, 11:13 PM

It's a fairly straightforward job, I did follow ps2cho's tip from a previous thread and used a large breaker bar braced against the frame and bumped the starter to loosen the 27mm crank bolt. I ended up buying the locking tool on ebay for when I tightened the bolt though, I didn't want to risk breaking anything when tightening it to the 300nm spec

Unless you really feel like going through the trouble of dropping the oil pan, I'd just cut that front section out of the pan gasket and use a bit of sealant in the corners.

Just follow the factory manual and you should be good to go.

ps2cho · #7 12-30-2014, 10:25 AM

At 300k...it may be worth replacing the chain as well...I'd do it all at once.

Hit Man X · #8 01-04-2015, 11:44 PM

Yep, chain is cheap enough. Good call.

I learned years ago not to try to bypass using the proper tools when I broke something on my E23 745i as I did not want to buy a $40 crank tool. I bought that tool when I replaced the front main when I performed a valve job on the car.

Figured that was the leak, not the lower cover. So now I have to go in there again.

Besides that, the tool I think also works on my 603. Unless it is the 617 tool that does. I forget. Maybe it is the M116/7.

I know I purchased them all for that reason.