This weekend I'm going to do another DIY writeup (like the ball joints http://www.peachparts.com/Wikka/W124BallJoint ) for replacing the gasket on the top timing cover at front, aka the u gasket. I've done this before and used Hylomar and had good results but I know there is a bit of debate on which sealant to use. Before I do the DIY write-up (and the repair) I'd like to poll everybody for their recommendation.

Thanks!
Robert

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89 300te 222,222
92 300e 190,000

Well as you may already know, I gave in and bought the oem stuff since that was the only one available in my area, and I didn't want to have to order by mail. Feel free to look at my thread:

http://www.peachparts.com/shopforum/showthread.php?t=102977&page=5&pp=15&highlight=loctite

Make sure you look at:
Post #51 on Page 4 and also Page 5

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1989 300CE Astralsilber/Schwarz
1992 300CE Schwarz/Schwarz

Robert:

Forget the sealant. It's like the oil/coolant debate. There are several sealers that work on the U-Gasket. The process that you're about to prepare is what counts.

Thanks for taking the time.

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'91 300-SEL

I used the black OEM stuff from the dealer and it has held up fine for several months now - I think proper preparation i.e. cleaning of the mating surfaces is the most critical step. If the mating surfaces are 110 percent oil-free and you torque properly, you could probably use bubble gum and it would hold.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Don't take the sealant choice lightly. This is a very specific application for sealant. The key is that the sealant has to be slimey slick so that you can slide the cover rearward without displacing the seal, but it has to have some body to it so that it will goop up in the corners.

I'm sure that there are other sealants that will work, but you would have to experiment to find it.

When starting the shaft seal over the camshaft, use your fingernail to ensure that the seal does not "fold" and slips over the shaft properly. Put a light coat of oil on the sealing surface of the camshaft before doing this.

Good luck,

I did this job earlier this week.

I used a sealant from FastLane called, I believe, Curil. It was in a tube with German writing all over. It was black and looked and smelled exactly like some old Permatex gasket stuff I've used in the past.

Oh, and no leaks.

And, I installed the new camshaft seal AFTER the cover was in place. Seemed safer to do it that way.

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2012 E350
2006 Callaway SC560

I just completed a valve/timing chain redo on my 1992 300SE and after ScotchBriting all gasket surfaces and liberal use of contact cleaner, I installed the lower cover without the crank seal and used Permatex Ultra Grey gasket maker for about $6.00. I set the U-shaped seal in place using the permatex. When it had set (24 hours) I cleaned it up with a razor blade and then installed the top cover using the Permatex. It has been 4k miles and it is dry as a bone. I think allowing the 24 hour setup prevented the U-seal from slipping out of place. As far as having to use the MB sealers, the cost is much greater. To me, metal is metal, rubber is rubber and if the Permatex works on Fords and Chevys when applied properly then it will work on MBs if applied properly also. Time will tell.

Tim