So what is the recommended sealant to ensure a leak-free engine? I'd like to get the right stuff to seal the front cover on my 603.

Thanks

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Chief

1991 350SD

I use Permatex Ultragray RTV.

Sixto
87 300D

The Much Vaunted FSM calls for an Anaerobic (Cures in the absence of Oxygen)Sealant.
(It's the equivalent of Permatex 574)
with a couple of dabs of what they call "Black Omni" in another location.[which is another Permatex Product only it's an RTV.]

[The Anaerobic sealant adds "Strength" to the Bond between the Aluminum T.C. and the Ferrous Block.]

__________________
'84 300SD sold
124.128

I remember using an anaerobic on my M103 front cover years ago, but it leaked again after a couple years. I hate RTV, as it always seems to migrate.

__________________
Chief

1991 350SD

I've been successfully using something called Ultra Copper for years without any issues as long as you do not apply too much.

__________________
Jim

Here's the stuff:



I use it for the EGR exhaust plate as well.

The factory recommended product is called "Hylomar". That is what I use.

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Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

LOL. "front timing cover" as if there were a rear one.

I have used Aviation sealant on nearly everything over the years with good success. The last few years I have used a (Permatex?) product called "Great Stuff" maybe? It is super strong RTV product that has not leaked for me yet. I have used it on a variety of things on our race cars and sometimes have difficulty getting it back apart. This is a good problem to have.

Best of luck and I hope you have a sense of humour.

__________________
83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.