Oil leak
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Joined: Oct 2023
Posts: 6
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From: Sweden
W203 W639
Oil leak
Hi I have a Mercedes 2013 with a 3.0cdi engine ( om642). It’s leaking a lot of oil but I’m a little unsure if it really is the oil cooler sealings. There is a little oil around the drain hole on the left side of the engine but there is a lot of oil inside the bellhouse. If the oil cooler is leaking I guess it would be oil outside the engine and bellhousing and not inside the bellhouse. When I remove the black rubber cap located down on the bellhouse there is a lot of oil inside the bellhouse. I’m thinking it should be the rear crankshaft sealing leaking or can there be so much oil inside the bellhouse when oil cooler sealings are leaking?
Out Of Control!!
Joined: Apr 2019
Posts: 12,272
Likes: 6,918
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
beyond dirty leaks...
Hi I have a Mercedes 2013 with a 3.0cdi engine ( om642). It’s leaking a lot of oil but I’m a little unsure if it really is the oil cooler sealings. There is a little oil around the drain hole on the left side of the engine but there is a lot of oil inside the bellhouse. If the oil cooler is leaking I guess it would be oil outside the engine and bellhousing and not inside the bellhouse. When I remove the black rubber cap located down on the bellhouse there is a lot of oil inside the bellhouse. I’m thinking it should be the rear crankshaft sealing leaking or can there be so much oil inside the bellhouse when oil cooler sealings are leaking?
- The oil leak color looks very active and fairly clean yellowish... engine or steering oil??
The picture looks like oil is coming down from higher than bellhousing plug - Meaning gravity says your leak is not from the rear main seal, yes
-- Usual W212 engine leaks are from:
- valve covers RTV get breached
- coolant/oil heat exchanger mayo!
- oil filter housing gasket is a favorite
- Timing covers can leak productively
-- Do you have a "power steering" pump or an "electric steering" rack?
-- Try to search top to bottom and front to back to pin your main offenders.
-- Normally you go at fixing one leak, then the next leak and the next leak ... until you deal with PCV breather hose (kit) all gunked shut ✌️
Crankcase blow-by gases need to find an escape route. Pressure blow out the weakest seals...
Does your engine have camshaft rear plug covers?
🤞
++++ Part II: sprayed all around ? Hope not!
It may be rear main seal is spraying oil all around from converter spinning it.
Rear main seal repair is labor intensive and may not extend useful life... what cooks this seal is the high heat from tranny ie. it is also near end-of-life.
> Use oil additive to soften gaskets, refill oil until last day or recycle now.
Last edited by CaliBenzDriver; Oct 30, 2023 at 01:51 PM.
Member
Joined: Nov 2018
Posts: 213
Likes: 119
From: Brazil
W212 (212.065/276.820)
My two cents... on diesel engines oils gets pitch-black so from the pictures it seems to be engine oil. Again, the pictures show oil leaking from the center-line of the bell-housing, trough the blank cover of starter (which is connected to the bell-housing) and trough the bell-housing drain cover (used to drain the TC). It seems like a rear main seal leak to me.
Out Of Control!!
Joined: Apr 2019
Posts: 12,272
Likes: 6,918
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
My two cents... on diesel engines oils gets pitch-black so from the pictures it seems to be engine oil. Again, the pictures show oil leaking from the center-line of the bell-housing, trough the blank cover of starter (which is connected to the bell-housing) and trough the bell-housing drain cover (used to drain the TC). It seems like a rear main seal leak to me.
