M112 V6 leak in the timing chain cover/guiderail

[KillerHERTZ]

I have had a tiny oil leak for the past year at the front of my engine. Yesterday/today my car has had a major service/MOT (which it sailed through of course ) and, after speaking to my mechanic he showed me where he thinks the leak is coming from.

After looking at the engine diagrams on the PC, and the car itself he said he thinks its a leak on the timming chain cover/guiderail blanking plate, he thinks its one of the holding pins has been lost/moved over causing the tiny weap and it may have fallen through?
We have left it as it is as it will be a huge job gaining access to the said area, maybe even having to remove the engine! and the fact that very little is lost over time.

Does anyone have any knowledge of this fault? known problem?

(Why does your car run the best it ever does once it has had a service? )

 

[lynall]

Iirc there was a product sold for classic cars like a stick of candle and was designed to be rubbed into casing joints to cure minor oil leaks without a major strip down.



Lynall

 

[stevesey]

Any chance of pin-pointing the location of this "blanking plate" - couldn't see any blanking plates on the russian site page for timing chain cover

I replaced the oil-cooler seals a few months back to fix a small weap in that area - assume this is lower down (and inaccessable)

 

[KillerHERTZ]

From memory of looking at his software it looked like this (view from infront of the engine):

The grey thing the blanking plate, the dot the pin. (Drawn with PS in a hurry sorry - you get the idea though! )

 

[stevesey]

Doesn't look anything like the russian site pic (linked above) - but could that be part no 20, different shape, right place.

Mine was oily because it's directly below the oil cooler - have you checked the bottom of the oil cooler/filter housing (with your fingers to check it's not running down from there?)

 

[lynall]

Pivot pin for chain tensioner or guide.

Here http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=202088&M=112%2E915&GA=722%2E696&GM=716%2E626&CT=M&cat=19X&SID=05&SGR=015&SGN=01

I remember having head of wifes old m104 and iirc there was a little blanking cap over the guide pin, but i could be wrong that was a long time ago.

Here http://www.benzworld.org/forums/w163-m-class/1291065-oil-leak-4.html maybe useful i know they are yanks but beggars cant be choosers!



Lynall

 

[rpe2]

Seen 3 of these 112's leak in this area now.

Each time it has been the seals going hard (items 17/23 in the link below) and leaking between the oil filter casing and the heat exchanger(items 11 & 5 in the link below), if you run your hand around the joint on the bottom, you may find oil there. One instance I came across leaked onto the poly belt and it slipped off etc..

http://www.detali.ru/cat/oem_mb2.as...GM=717.464&CT=M&cat=19X&SID=18&SGR=060&SGN=02

The shocking thing is the £ of the seals, circa £30 the pair

Richard

 

[rpe2]

Sorry just read the thread properly, sounds like the same as Stevesey.

Richard

 

[lynall]

Read the thread properly we wont have any of that thank you

I never do, the amount of editing i have to do



Lynall

 

[KillerHERTZ]

Pivot pin for chain tensioner or guide.

Here Êàòàëîã

I remember having head of wifes old m104 and iirc there was a little blanking cap over the guide pin, but i could be wrong that was a long time ago.

Here Oil Leak - Page 4 - Benzworld.org - Mercedes Benz Discussion Forum maybe useful i know they are yanks but beggars cant be choosers!



Lynall

Thats exactly it! thanks!


Thanks to everyone else for repling aswell. Im gonna live with it for the time being as it only drinks about 1 extra litre per 6 months if that!

 

[stevesey]

So it's parts 29 and 20 here you need? (according to post 37 on benzworld) I'll be keeping any eye on mine now - think it's OK though.

Shouldn't be too difficult shoudl it - I can see the cover on mine. With the belt off there should be enought room - possibly more on yours as it has an electric fan (smaller fan ducting = more space at front of engine).

 

[stevesey]

Was thinking about doing mine anyway as the oil cooler seals were very brittle when I did those, and reading the benzworld thread people were saying the gasket here was often cracked/brittle so if the oil cooler seals had gone brittle I was expect this one has gone the same way.

Gave a good wipe around last night, just been out for a drive and there is fresh oil on the underside. So will get this done next weekend.

 

[KillerHERTZ]

So it's parts 29 and 20 here you need? (according to post 37 on benzworld) I'll be keeping any eye on mine now - think it's OK though.

Shouldn't be too difficult shoudl it - I can see the cover on mine. With the belt off there should be enought room - possibly more on yours as it has an electric fan (smaller fan ducting = more space at front of engine).

Not sure TBH as the image he had was much clearer, he only thinks thats the fault at the moment and asked me what he would like me to do before he continues. Instead of getting them to remove most of the engine bay and finding it was somthing else we decided to leave it as it is as its only a tiny trickle of oil over months...

After reading the links etc, looks like he was right afterall

 

[stevesey]

Replaced mine the other week - here a couple of pics.

Old (left) and new (modified covers) - old cover still had the plug in which I tranferred to the new one.




With a 3/8 socket set using the short extension, it's easy to get access to the two nuts, you just need to flex the fan cowl a little to fit the ratchet and extension in (the belt flexes out of the way easy enough for the bottom bolt). The radiator hose and oil cooler obstruct visibility so you are working about 50% by feel - make sure you fit the new cover the right way up (otherwise you have to undo and refit ) a small mirror helps for checking.

My old seal was very dry and brittle, so due for repacement and the part cost less than £10 so well worth doing in the long run.

Although having cleaned everything as part of this I still have a leak from the oil filter housing (bottom seal), but there is an oil change due during the next two weeks so I'll get that done then.