I am also having some oil leak in the front cover, and is looking to replace the U-seal. After reading Eric's DIY, I am thinking whether it is worthwhile to try the external method first, namely, filling the leakage point with sealant.

What do you think?

kyericho, definitely try the external sealing method. The trick is to get the leak area completely clean so the sealant will adhere properly.

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Fred Hoelzle

Hey guys,

I am doing this for a 97 E320, same engine M104. i have this U seal and was wondering if i should let it set once i have everything in place. i am going to be using the MB sealant. if i put everything back on...can i start the car right up? or should i wait for the seal to set?

First off, let me thank all who have so graciously posted here, incl. the thread starter, Eric Silver, et al.

I’m truly impressed by the time, dedication & pics some of you have posted and your willingness to share your DIY experiences.

As a dinosaur, most of my input will likely be C&P; my cell phone lacks even a camera. That said, I try to be explicit and accurate whilst so doing. Someday this may change as I enter the 21st century.

Eric, I think your trimming the prone-to curling channel gasket is a mistake; YMMV. That said, if it worked for you, so be it. But I think you may have overlooked something like pin-removal in your disassembly. Not that I have even attempted this fix yet. I must say, you did a stand up job on your post.

After viewing your pain & others for hours on end, I need to see if my corner [Passenger-Side Timing-Chain Seal-Channel] is even leaking. If yes, it is significant or can I live with it. If I had my druthers I’d replace it all, even the head gasket, if needed, but I need to press my 1994 E320 into service ASAP.

What tempts me is I’m just changing the plugs for the first time since April, 2012, & believe I need a new Valve-Cover gasket. Some oil was pooling at the base of some (like 2) of my plugs.

Before you criticize my maintenance schedule, understand since April, 2012 to present, Jan. 2019, I’ve put on it a mere 14,000 miles, period. Bought it used w/ 104K, now getting all worn out @ 120K. I plan on keeping it till the dirt nap; then my wife can continue getting spoiled in it.

I’ve always had a hard on for the M-B straight six.

Having several old cars driven all the time, no one gets too many miles per annum.

When my wife was driving to & fro with it to work, my beloved W124 - E320 went into Limp Mode; that’s what sent me down this rabbit hole, the infamous, biodegradable, Main Wiring Harness. Up till then it ran just fine, though I was well aware this original octopus would die soon, and I already have a newer used unit awaiting Install. But I digress, that’s another thread.

My Q:

Am I the only one here to ponder using an aluminum-epoxy like JB-Weld, externally, on the Gap that the brilliant Benz engineers forgot to fill? This is lieu of flexible silicone sealers.

I’ve never used the product before, but bought some, as it apparently may work wonders on a clean surface, depending on needs.

Am thinking the Gap could possibly be sprayed w/ CDC or any other brand of Brake Cleaner, if one can get the straw in there, then Filled w/ an aluminum-epoxy.

Brake Cleaner gets used in a pinch to blow gunk out of pistols shooting cheap & dirty Russian patronen, & it will even blemish the older Tennifer-type finish on a Glock slide. I’m not sure what it MIGHT do to a rubber gasket though.

I’d hate to spray & pray, then spring a leak, or aggravate one, assuming I’m leaking at all. Perhaps Electrical Contact Cleaner would suffice? In days of old, we cleaned a greasy block on the cheap w/ leaded gasoline & a paint brush.

Any ideas?

Thanks , Jim. I had same leak on my.

I have 121,000 miles on my 94 M104 E320 engine, of which at least the latter 40k was while running only Mobile 1 full synthetic. I am about to change the upper timing cover gasket, is it recommended to also change all the plastic timing chain guides while I am in there, or is that premature or unnecessary?