'01 S600 Oil Leak

[dreamline]

My '01 S600 leaks oil - a few drops overnight, and leaks onto the left exhaust pipe (below the manifold) when I drive uphill - I can see and smell oil burning.
I've looked around, but can't seem to find the source yet.
Does anyone have any experience with oil leaks in these engines?
Thanks!

[trueog]

Originally Posted by dreamline

My '01 S600 leaks oil - a few drops overnight, and leaks onto the left exhaust pipe (below the manifold) when I drive uphill - I can see and smell oil burning.
I've looked around, but can't seem to find the source yet.
Does anyone have any experience with oil leaks in these engines?
Thanks!

I think its you're head gasket. I have the same problem with a C-Class, and was told by the dealer of a small head gasket leak. Considering you're car's V12 engines only worth about $15 000 if it dies on you, i'd get it checked out ASAP...

[DR.DIESEL]

Where does it drip on the exhaust? On the side or behind the engine?
Is there oil on the black plastic ignition rail that covers all the plugs?
Is there oil where the black intake pipes meet the intake mainfold?
It is not very likely a head gasket since this engine uses very good
sealant for the head to block contact area.
Is the ABC fluid reservoir low? this is also very common to leak onto
exhaust. See dealer for recall/service campaign.
DR.D

[trueog]

Originally Posted by DR.DIESEL

Where does it drip on the exhaust? On the side or behind the engine?
Is there oil on the black plastic ignition rail that covers all the plugs?
Is there oil where the black intake pipes meet the intake mainfold?
It is not very likely a head gasket since this engine uses very good
sealant for the head to block contact area.
Is the ABC fluid reservoir low? this is also very common to leak onto
exhaust. See dealer for recall/service campaign.
DR.D

THere you heard it, he knows more then me. So it's not a head gasket leak, i wuz wrong...

[DR.DIESEL]

Crankcase oil builds up in these M137 motors right where the intake plastic pipes and the manifold meet. It will drip out of the joint.
There are some known issues with the PCV system on these cars.
If you have warranty or service contract, you might want to use it.
Regards
DR.D

[skiier3_9]

From your other posts, Dr. D., it sounds like anyone with a 00 - 01 S600/CL600 (m137) is better off selling their car than dealing with the poorly desinged/problem ridden engine.

Thoughts? -- I'm certainly no expert

[dreamline]

I absolutely love this car - and the V12 is a large part of the attraction.
It has the incredible, smooth power of a small displacement / 12 cylinder engine that's just unlike any V8 experience. It has great low end torque, but that's just the beginning - it winds from 3200 to 6000 rpm in a split second.
It's scarcely slower than my 71 Corvette with 502 ci Merlin big block, AND it's everyday driveable, has every creature comfort and has that MB feeling (Je ne sais quoi).
As a car enthusiast, I will make certain concesions for driving a car that totally turns me on. Does this car require more maintenance and repairs than a Lexus or even a Chevrolet, certainly. Did I know that it would cost more to maintain? Definately, but it was a concious decision. It's still better than English or Italian cars. I don't think it's a poorly designed engine and it hasn't had any real issues until now. My S600 has actually been a little better than most S Class cars I've read about on these forums.
It's got some issues, but when you're in love, the good times outweigh the bad, and you go on.
Just my $.02.

[skiier3_9]

I was only referencing Dr.D's comments in this thread:

M137.9 V-12 Reliability

[ILUVMILS]

Originally Posted by DR.DIESEL

Crankcase oil builds up in these M137 motors right where the intake plastic pipes and the manifold meet. It will drip out of the joint.
There are some known issues with the PCV system on these cars.
If you have warranty or service contract, you might want to use it.
Regards
DR.D

Very true however, I've found the most common reason for oil in the intake is due to the Cylinder Shut-Off (CSO) feature. The M137 can shut off the entire left bank under certain conditions to improve fuel economy. This can allow blow-by due to the pressure/temperature differences of the inactive cylinders. Fortunately, the CSO can be de-activated with SDS. If I owned any M137 equipped MB, the first thing I'd do is de-activate CSO. Eventually the oil in the intake will cause ignition mis-fire which will quickly damage the (very expensive) ignition coils.

[Hatterasguy]

Originally Posted by dreamline

I absolutely love this car - and the V12 is a large part of the attraction.
It has the incredible, smooth power of a small displacement / 12 cylinder engine that's just unlike any V8 experience. It has great low end torque, but that's just the beginning - it winds from 3200 to 6000 rpm in a split second.
It's scarcely slower than my 71 Corvette with 502 ci Merlin big block, AND it's everyday driveable, has every creature comfort and has that MB feeling (Je ne sais quoi).
As a car enthusiast, I will make certain concesions for driving a car that totally turns me on. Does this car require more maintenance and repairs than a Lexus or even a Chevrolet, certainly. Did I know that it would cost more to maintain? Definately, but it was a concious decision. It's still better than English or Italian cars. I don't think it's a poorly designed engine and it hasn't had any real issues until now. My S600 has actually been a little better than most S Class cars I've read about on these forums.
It's got some issues, but when you're in love, the good times outweigh the bad, and you go on.
Just my $.02.

Very true, well said.

MB makes some awsome V12's. They are so fun to drive that any minor issues can be overlooked.

Look at it this way, no $5k timing belt changes!

[dreamline]

Thanks for the suggestions of where to start looking for the leak and advise about the cylinder cutoff (I think my extra heavy right foot has helped the CSO problem so far).
I'll start looking this weekend and I'm sure I'll have more questions next week!

[DR.DIESEL]

Very true however, I've found the most common reason for oil in the intake is due to the Cylinder Shut-Off (CSO) feature. The M137 can shut off the entire left bank under certain conditions to improve fuel economy. This can allow blow-by due to the pressure/temperature differences of the inactive cylinders. Fortunately, the CSO can be de-activated with SDS. If I owned any M137 equipped MB, the first thing I'd do is de-activate CSO. Eventually the oil in the intake will cause ignition mis-fire which will quickly damage the (very expensive) ignition coils.

True. However, I have found on most of these motors if the passenger side front cover oil seperator is clogged and not draining, the manifold will fill with
oil faster than anything. See DTB P-B-01.20/13 as follows.

SUBJECT: Models 215.378 and 220.178 with Engine M137
Engine Running Complaints In Conjunction With Blue Smoke and/or Hydrocarbon
Odors Smells During First Start Up
If you receive customer reports in the above model vehicles equipped with engine M137 of engine running
complaints / misfire in conjunction with blue smoke for several seconds during engine first start-up,
hydrocarbon odors during engine first start-up, and/or excessive amount of standing oil in the intake
manifold, please refer to the following cause and remedy.
Cause: PCV (positive crankcase ventilation) System intake assembly (front cover, right cylinder head) oil
condensation drain clogged with oil sludge. Refer to Figure 1 for part location.
Remedy: Remove and disassemble the front cover assembly of the right cylinder head. Refer to WIS
document no. AR01.30-P-5700L, up to and including step no. 14, for R&R of the front cover assembly of the
right cylinder head. Inspect oil condensation drain for clogging (Figure 2) and clean out the oil sludge
blocking the drain. Reassemble and reinstall the front cover assembly of the right cylinder head.

Regards,
DR.D

[DR.DIESEL]

Nah, the head doesn't have to come off to fix this. Just the front cover of
the right head.
The Main PCV suction line is connected to a poorly designed oil seperator in the front cover. Crankcase fumes are sucked in (with a ton of splashed oil!)
directly behind the cam sprocket and chain. There is a BS little drain shaped
like a boat anchor to drain off all the oil.
The problem is, the drain gets plugged and oil quickly overwhelms the oil
seperator. The PCV system is then free to suck pure oil up into the second oil seperator in the valley of the block and then into the throttle
actuator to dispense it into the manifold and combustion tract.

Easy fix to clean and good service will prevent from occuring again.
Dr.D

[DR.DIESEL]

Merc 12 cyls have got to be the most poorly designed motor in existance.

Actually, the Biturbo 12's from 2003+ have been very very reliable.
We have sold a ton of them and they are never in the shop.
The 1.8l Kompressor M271 4cyl picked up the "worst engine ever" banner
and ran with it until it got axed 6 months ago.
M137 V-12 RIP 2000-2002
M271 4cyl RIP 2003-2005
Somewhere there are powertrain engineers hanging in some castle
by their thumbs.

DR.D

[dreamline]

It was the PCV and hoses that were leaking oil all over the place.
I'll have to get to the front cover drain & see what's cookin' up there now.
I guess there's no M275 engine in my immediate furure. Maybe one day.