Confused about MB sealants (engine mating surfaces) Loctite 5900 Permatex right stuff
 

Hoping someone can clear this up. Doing tons of searches on this site and others to see what sealants guys are using for a front upper timing cover job on a '94-95 E320. Or, in general, what MB is recommending today for most engine applications.

Can anyone tell me the differences between these MB sealants?

002-989-45-20
-also
0029894520 - $39.75
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002-989-73-20-10
-also
002989732010 - $6.90
(when I do a search on fastlane, it lists 003-989-98-20-10)

Is this what is known as loctite 5900? Or Permatex "the right stuff"?
---------------------------------
003-989-98-20-10
-also
A 003 989 98 20 10
-also
003989982010 $11.63

Does this MB part# supercede 002-989-73-20-10?

And is this what is known as loctite 5900? Or Permatex "the right stuff"?
-----------------------------------
001 989 61 20 10
-also
001989612010 26.25

Steve Brotherton lists # 001 989 61 20 10 used for the dabs in the corner.(upper timing cover). And # 002 989 47 20 10 for the metal-to-metal surfaces.

The link to his fantastic writeup. http://www.continentalimports.com/ser_ic100345.html

Man, I would really appreciate any guidance on sealants. I'm about to head out in a minute (6:30 a.m.) to try and round up some Permatex "the right stuff" so I can do the cover today. But I may hold off until I can get the correct MB sealant.

I've used 003-989-98-20-10, but it takes forever to cure - and I'm about out!
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Many, many thanks!

MB part number 003-989-98-20-10 is Loctite 5970...

That is the ONLY sealant that you need for metal to metal surfaces on MB engines!.. Does require at least 1-2 hr setting time

DOC, would applying that sealant around the oil pan effectively stop/reduce a leak from the oil pan gasket, which apparently is a major job to replace in a 1988 w124? Thanks.

Thanks MBDoc --- I called my local MB dealer, and they verified that is the sealant they use/recommend for nearly **all** applications.

But --- I did end up getting a "can" of The Right Stuff. And used it earlier today on my upper front cover reseal. It really seems to dry fast - seems like good stuff. I'll report in another post how it did for me.

Thanks again.

BTW - I moved to Texas from Lilburn, Ga. I lived off of Killian Hill (south Indian Trail) just south of Hwy 29. I've been to Snellville several times ;)

Just to follow up. Did **two** front cover reseals on my '95 E320 this weekend using "The Right Stuff". Well, it was the WRONG STUFF. The cover is still leaking from the passenger side corner.

Now, I know my head gasket has receeded. And I probably need to replace it with the newer design gasket. But I thought I could at least temporarily stop things from leaking. Wrong!

I will order the MB stuff MBDoc recommended and try again this next weekend. And if that doesn't do it, it's time to pull the head.

Here we go again! Basically this is a controversial topic. I did a little write-up on it a while ago:
http://www.peachparts.com/shopforum/tech-help/120808-another-diy-top-timing-cover-m103-hylomar-right-stuff-larrybible-benzmac.html
and
http://www.peachparts.com/Wikka/M103TimingCoverReseal

I'm not sure what the question is. The Doc is right, use MB black silicone sealant and it works quite well if the procedure is done correctly. It sets a bit quicker than RTV black so the work needs to be done more quickly so all is in place before it starts to skin. As for the head gasket, used to love doing them. Made a bit of money doing it. Could do two a day with a long lunch. Ask Doc, I'm sure he did a couple.
Bill

On my M104 I used The Right Stuff based on recommendation of a guy who has built a lot of AMG 104's, that plus nobody sells the Loctite 59XX products around here. He says no matter which sealant you use, the secret is in the preparation. An interesting side comment he made was to just plan on this job being on a 4-year PM cycle, like the head gasket. Drive it 4 years, do the head gasket and timing covers. He also said another thing he does is to apply the sealant, set the covers in place, run the bolts up just snug and then let it sit overnight, then torque the bolts to spec the next day.

After researching this for months, I have come to the conclusion that the realistic issue here is that this is a hopeless sealing job/physical impossibility to expect leak-free performance over the long term. There are just too many metal parts and unequal joints moving around down there, too much temperature cycling, too much exposure to oil for any seal to last any length of time.

There is a sign on the wall in my local import parts shop that says 'If It's German, It Leaks'. :wallbash:

True, it wasn't easy to find - even on the internet machine, but it can be found by MB's part number 002989472010 or WorldImpex's sku 658804 (for the MB stuff) or try the BMW part number OEM: 83-19-0-404-517 / 83190404517. This yields Loctite 5970 for $23.40. No affiliation with WorldImpex - they're usually a bit high, but have proven to be good for Audi dealer parts. :cool:

002-989-45-20 is a clear RTV silicone sealant. I haven't had any trouble with leaks when used wherever the FSM specifies it...

http://www.w124performance.com/image...ant2_clear.jpg



I'm not sure if blindly substituting the black stuff (003-989-98-20-10) in place of the clear is necessarily the best idea.

http://www.w124performance.com/image...ant3_black.jpg



I don't use either of the above sealants for metal-to-metal surfaces without gaskets. MB specifies anaerobic case sealants for those items, such as timing covers, and the M119 front head cover:

http://www.w124performance.com/image...it-FD-3041.jpg


:euro:

A little off topic...
 

I just replaced the oil pan gasket in my 103. (engine is out.) I was under the assumption that no sealer is needed there, just the gasket.. Am I wrong?

I believe that gasket should be installed dry, since the FSM does not mention the use of any sealer for M103 job # 01-3100. So yes, it appears you did the right thing.

:chinese2:

I'll bump this 'cause I'm a bit confused myself - I have seepage from the right front oil pan right around that bolt - exactly like the pic in the STAR service manual which says to use the 002 989 45 20 sealer. Is this in lieu of replacing the oil pan gasket? Is the intent to just try and seal the area that is leaking without dismantling anything?

Thnx,
Bill

Reminders
 

Bump

Bill, which bolt are you referring to? And which service manual procedure? From memory, on the OM603 oil pan the clear silicone sealer is only used in a small dab at the 3-way junction of pan, block, and timing cover. Depending on where exactly your leak is, you may be able to apply some RTV externally as quick fix.

The M104 front cover being discussed previously is a different animal; also on the M104 the fan bearing bracket will leak oil if the orange anaerobic sealant isn't used on the bolt threads as noted in the FSM... I have a feeling a LOT of people don't do this, and then wonder why they have a leak.

:stuart: