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

__________________
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?

Thanks , Jim. I had same leak on my.

Thanks to EricSilver, for a great tutorial.

This oil leak was really annoying me.

I had oil leaking all down the side of the engine block, and was contemplating removing the cover and resealing it. I can confirm that after applying high temperature sealant to the corner of the timing cover as suggested. The oil leak has been completely fixed.

I feel as though I should let you all know of the results.

Here is a picture; it’s not pretty and quite difficult to get a descent picture but no leaks.

Thanks again and I hope this helps someone else.

Cheers

Attached Thumbnails

   

Hello
I replaced mine recently, well the seal had a 2 cm crack. I replaced it with a brand new one, used silicon glue but it start leaking again, (didn't even last a day) I had to remove the cover again and found the seal is in pretty bad shape! it had a 5-6 cm crack or so. but it was firmly in its place...so what do you think? is it any point while putting cover and seal back together?
If I knew I will be forced to remove all things 3 times, I would live with the leak as it was really negligible.

For what it's worth, I just spoke with Curtis at Permatex and grilled him for info on different sealant options. He clarified that the Ultra Copper is designed for exhaust applications with extreme heat. Ultra Black is designed for applications where gaskets don't quite cover gaps due to poor machining on older Ford and Chevy engines. He confirmed that Ultra Grey is designed for applications like the tip of the front cover seal - high tensile strength, high vibration and flex tolerance. The MB clear RTV (002 989 45 20 10) seems to be harder and harder to come by and getting more expensive when it can be found. Hope this helps.

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?

sure you can try sealing from outside..interesting. But properly done in the headgasket repair procedures...you can quite successuflly do the timing cover wihtout these measures..YOu just need to tilt the cover toward the engine which pinches the gasket at the near corners to the head..and lifts the far side over the ridge in the gasket..DO NOT install the guide rail pin until AFTER the cover is in place..and when its close enough to pop it under the centering pins on the cyl head..it will then move into place at the base gripping the gasket perfectly..Then you can install the guide rail pin and bolts..(I had to do repeated removals on my car and got pretty good at the RR ) Some guides install the guide rail pin prior to the timing cover and thats crazy..It comes out first, goes in AFTER..Mine doesnt leak a drop..Yes, a bit of sealant where indicated..very little on the mating surfaces of the metal-metal or none..

Wish you were here 5 years ago, when I did that "repair."

There may be another, simpler possibility:

There is a high-temperature version of POR-15 that is (or should be) impervious to oil. It should be theoretically possible to simply paint that onto the spot where the gap is and seal it for good.

But that is just speculation.

__________________
2008 E350 4matic / Black/Anthracite

------------------------------------
Gone but not Forgotten:
2001 E430 4matic, 206,xxx miles, Black/Charcoal
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black

I did the cyl head removal three times and finally got the system down..I see you were struggling with guide rail pin alighment and the tutorials often dont indicate it goes in AFTER you get the cover on..Easily drifted in with its tapered point allowing it to center into the guide rail..I was struggling with a bad vacuum modulator valve causing smoking and pulled the head thinking I messed up something when it was the VM all the while..But the gasket needed replaced anyway..so nothing lost.

Great job documenting and sharing all you did!

Has a final decision been made on the best sealant material to use if you are only trying to fill the gap (i.e. not removing the cover)?

I'm planning to change my drive belt on my 94 E20 wagon soon and will a chance to access this area. I'm pretty sure I have the same leak.

I would think anything heat resistant and sticky enough to stay attached to that small area will work just fine. I still like the idea of POR-15 High-Temp Paint in, and around, the gap.

__________________
2008 E350 4matic / Black/Anthracite

------------------------------------
Gone but not Forgotten:
2001 E430 4matic, 206,xxx miles, Black/Charcoal
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black

Just today successfully resealed the upper timing cover on my '95 E320. It's a fairly simple job except for the problem of the green seal wanting to roll over when the cover is replaced. Big problem. After many failed attempts to get the cover on, here is what finally worked. I cut a piece of flat, smooth plastic approximately 1.5" x 3" from some packaging material (it happened to be packaging for several small rolls of electrical tape). I later measured the thickness of the material at 0.5 mm. I installed the seal, lubed it and both sides of my shim with motor oil then started the cover into position. On my engine the seal always rolled in approximately the same spot, so before the bottom of the cover rubbed that spot I pushed the plastic shim in between the cover and the seal. I tapped the cover into place with a rubber mallet then pulled the shim out with a pair of pliers and the seal was seated correctly.
Very happy to have stumbled upon a solution as my C36 is leaking from the timing cover, too.

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?