W212 E350cdi Differential thread sealant

[Webster200x]

Hi there everybody I got a question about the differential thread sealant is it necessary to use A0029892371 MERCEDES-BENZ, ADHESIVE or OMNIFIT 100M - Thread sealant - Henkel Adhesives (same as Mercedes branded one just under its original name) or have anybody used just regular thread locker.

 

[Petrol Pete]

I do not know the exact answer. But sealant and 'thread locker' are two different things - I suspect there are multi compounds out there - My guess is in some cases the bolt will need sealing due to the design of the diff/gearbox/tank/gasket/seal that it is holding a cover to and in other cases the bolts will need locking for the same (but different) reason.

Loctite (owned by Henkel) have many 'thread lock ' agents that appear to do the same thing but are very specific in their application.

Personally if I were to open a differential up I would stick with what the manufacturer recommends. or find out its exact spec and buy from the manufacturer. Mercedes Benz do not make sealants or thread locking agents.

I would not like to have to do the job twice . Let us know how you get on

 

[Webster200x]

I do not know the exact answer. But sealant and 'thread locker' are two different things - I suspect there are multi compounds out there - My guess is in some cases the bolt will need sealing due to the design of the diff/gearbox/tank/gasket/seal that it is holding a cover to and in other cases the bolts will need locking for the same (but different) reason.

Loctite (owned by Henkel) have many 'thread lock ' agents that appear to do the same thing but are very specific in their application.

Personally if I were to open a differential up I would stick with what the manufacturer recommends. or find out its exact spec and buy from the manufacturer. Mercedes Benz do not make sealants or thread locking agents.

I would not like to have to do the job twice . Let us know how you get on

EWA Said that the specified item should be applied to the fill and drain bolt but at nearly 100 pounds for 50g of product seems quite expensive for some threadlocker/sealant.

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[Petrol Pete]

EWA Said that the specified item should be applied to the fill and drain bolt but at nearly 100 pounds for 50g of product seems quite expensive for some threadlocker/sealant.

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Yes it is If its just for the drain/fill I am sure you will find a compatible product a bit cheaper. £1000.00/Litre is not uncommon in the specialised world of thread locking/sealing (and anything with an MB badge will be marked up a lot) so for someone who needs just a few drops it's tough search .

It's the type of medium to be held back , in this case diff oil , at what maximum temperature and what the plug/diff is made out of that determines what product to use. I am sure many have just wound some PTFE tape around it and 'job's a good un' . I know I have in the past , not always reccommended.

 

[Webster200x]

In that case i guess i'll have to order the one that the workshop manual specifies even tho i find it quite steep for 50 g of product that ill probably use it once and then not have to use it again for probably 5 years. Also my differential isn't making any noises its just preventive maintenance as i did with most parts of my car the only parts that are untouched is the differential and the timing chain/guides which i'm looking to replace in the next couple of months again no strange noises coming from the car.

LE: Here some pictures of WIS stating that you should use that sealant on the drain and fill bolts.

 

[W1ghty]

I haven’t used thread sealant on the diff on any of the 3 changes on each of my MB’s . I didn’t think you were meant to.
Mine are tightened to 50nm which is a fair amount for a non moving part .

 

[Ted]

I haven’t used thread sealant on the diff on any of the 3 changes on each of my MB’s . I didn’t think you were meant to.
Mine are tightened to 50nm which is a fair amount for a non moving part .

Fwiw I’ve done a few in my time and never used sealant without issue - even the final drive on the bike

 

[Webster200x]

I haven’t used thread sealant on the diff on any of the 3 changes on each of my MB’s . I didn’t think you were meant to.
Mine are tightened to 50nm which is a fair amount for a non moving part .

I take it it was fine and you never had a leak from that general area?

 

[W1ghty]

I take it it was fine and you never had a leak from that general area?

Never any leak on the total of 6 changes buddy

 

[Webster200x]

So I called the dealership asking them to purchase the differential plugs and they told me that the oil for the differential doesn't need to be changed and it shouldn't be messed with. My question is why would they tell me this as the diff is only a few cogs inside some oil and they aren't under pressure or anything.

 

[Monkeylegend]

I ran three E Classes to over 300k miles each and never changed the diff oil on any of them. My trusted main dealer and Indy said oil changes were not needed. Never had any issues or whining.

The current one is still running at over 320k, not by me, but I know the new owners, and all is ok.

This was/is on the 220 CDi so not sure if the 350 is any different.

 

[Jobsworth]

People rarely change the oil on non-lsd differentials, but it’s not a bad idea to change it occasionally. Strip and examine any unit that’s done a few miles and you will find wear and very slight pitting on bearing races and gear teeth. Those tiny fragments end up in the oil, and the sludge settled on the bottom of the casing is testament to this. Oil seals tend to harden on exposure to old oil too, and leak thereafter. 50-75k is probably a good mileage to consider a change if you hope to get 300k plus out of your machine.

 

[Webster200x]

I asked the dealer to order the parts for me as they said they don't stock the items also my car has 133k miles and it doesn't whine or make any noise whatsoever the only reason of replacement of oil is preventive maintenance.

 

[OneForTheRoad]

You'd run the risk of cracking the case using threadlock imho.

I changed the diff oil on my 04 w211 what came out was grey and gloopy . Car was only on 78k.

 

[W1ghty]

For the £20 diy cost using Fuchs oil I just do it when I do the gearbox service

 

[W1ghty]

I asked the dealer to order the parts for me as they said they don't stock the items also my car has 133k miles and it doesn't whine or make any noise whatsoever the only reason of replacement of oil is preventive maintenance.

Aren’t you just going to use Fuchs oil ?

 

[OneForTheRoad]

Aren’t you just going to use Fuchs oil ?

My merc dealer said he only sells mb oil , said he couldn't give a fuch .

 

[ToeKnee]

Just curious, is there a definitive list of when diff oil should be changed in various models? I'm doing the one in my R231 this year as it's 10 years, old albeit low miles, amongst other preventative measures, aux belt, tensioners etc.

 

[W1ghty]

Just curious, is there a definitive list of when diff oil should be changed in various models? I'm doing the one in my R231 this year as it's 10 years, old albeit low miles, amongst other preventative measures, aux belt, tensioners etc.

Only on LSD equipped vehicles and 4 wheel drives buddy . MB don’t change it otherwise , but don’t forget that’s because they warranty for 3 years

 

[ToeKnee]

Only on LSD equipped vehicles and 4 wheel drives buddy . MB don’t change it otherwise , but don’t forget that’s because they warranty for 3 years

I thought that might be the case as I've not come across any Mercedes info on the diff change. Thanks for confirming