W166.024 / OM624.628 - Excessive Oil Consumption?

protons

New member
Hello,

New to me W166 ML350 BT, 105k miles.

Purchased it from a used car dealer, when arrived I noticed oil level was at min, unsure of when oil was changed.

Drained oil, split filter open, looked fine. Foolishly didn't measure amount of oil drained.

8 liters of MB 229.52 (was unable to get 229.51) and a genuine filter installed.

Checked level and was near max, shop temperature, engine off for 1 hour (?).

After oil change I drove the vehicle for 100-200 miles while waiting on parts.

When parts arrived, I've done a lot of preventive stuff, including the PCV valve.

Picture of when I removed y-pipe, originally:
20220112-191610

Small amount of oil, normal?

Replaced PCV, belt, filters, idler pullies, etc.. to prepare for a long trip.

1000 miles later, checking oil 5 min after engine shut off resulted at min level on dipstick, waited a bit longer and level came up a few mm, below half maybe, hard time getting a good reading.

I decided to top off and set a reference point, I added another liter which placed me at right below max, with engine oil hot (90deg c).

500 miles later (today) I checked the level an hour after the engine has been off, oil temp is 32 deg c and I'm right below the half mark. I thought that while the oil expands when hot, checking an hour later will allow more to drip down to the pan from my last check, and I should have the same level as when I last checked.

Has anyone experienced something similar? Anyone found 9 liters to be more accurate? Any good advice on when to check level for most accurate readings? This oil does expand a lot when hot?

I'm reading horror stories about these engines drinking oil like there's no tomorrow, without external leaks or other obvious things (no mix with coolant, no smoke from exhaust).

I'm getting about 24-5 mpg, with full power and no obvious faults, but this is concerning to me because I think the vehicle is regenatring every 100 - 200 miles, is that normal?

Will appreciate any advice, Thanks.
 

lindenengineering

Well-known member
Reading this ↕a used car dealer! Uh Ho!
Probably bought it at used car auction following a trade in at a franchise dealership some place in town.
Why was it a trade is the question, and of course you don't mention the year, but franchise dealerships usually send trades to dealer auctions if more than 2 years old or have a doubtful history.

I suppose I have to ask why did you buy this ML in the first place when worldwide the RX 350 Lexus has stolen the show, and there are plenty available nationwide in the US?

Anyway the worst case scenario with these engine are oil rings going soft turning it into an oil guzzler.
The other is turbo shaft seal leakage allowing oil to pass over from snail housing to induction side and/or exhaust turbine side into the exhaust .
If the car has belly pans drop them, and look for oil loss being absorbed & hidden by the foam soundproofing which hides two important /concerning oil leakage areas , one the oil cooler and the other being the rear main crank seal.
Areas to investigate before taking putting wrenches on it -or taking it back to the use car place as a lemon and have Guido with you.
Dennis
 
Last edited:

protons

New member
Had decent service history according to the VMI, don't see the relevance of the rx350 here, different cars, returning it is not an option now.

Turbo had no play, cooler may have a small seep but nothing accumulates on the bottom of the bell housing.

If I need to remove the turbo to smoke test from oil feed, I will. I will also do the cooler at that time.

If it is the turbo, I should see smoke? If the consumption is not a product of my imagination, I have 300ml-600ml going somewhere 'internally'.

DPF regenerating every 150 - 200 miles of mixed city / highway driving is normal?
 

lindenengineering

Well-known member
Usual trade test to check for turbo oil carry over is remove the exhaust elephant tube. and run the engine @ 2000 r/m having a sheet of white cardboard a few inches away from the outlet. and check for oil spatter on the sheet and blue smoke to excess . .
DPF generation is high from your narrative suggesting oil carry over/oil guzzler like our shop van which had a similar engine it.
(AND customers with ML's & E Classes who have sought help with similar circumstances ,)
Since sending it back is not an option I can only hope you got it on the cheap.
All the best
Dennis
 
Last edited:

Bazookabob

Well-known member
Hello,

New to me W166 ML350 BT, 105k miles.

Purchased it from a used car dealer, when arrived I noticed oil level was at min, unsure of when oil was changed.

Drained oil, split filter open, looked fine. Foolishly didn't measure amount of oil drained.

8 liters of MB 229.52 (was unable to get 229.51) and a genuine filter installed.

Checked level and was near max, shop temperature, engine off for 1 hour (?).

After oil change I drove the vehicle for 100-200 miles while waiting on parts.

When parts arrived, I've done a lot of preventive stuff, including the PCV valve.

Picture of when I removed y-pipe, originally:
20220112-191610

Small amount of oil, normal?

Replaced PCV, belt, filters, idler pullies, etc.. to prepare for a long trip.

1000 miles later, checking oil 5 min after engine shut off resulted at min level on dipstick, waited a bit longer and level came up a few mm, below half maybe, hard time getting a good reading.

I decided to top off and set a reference point, I added another liter which placed me at right below max, with engine oil hot (90deg c).

500 miles later (today) I checked the level an hour after the engine has been off, oil temp is 32 deg c and I'm right below the half mark. I thought that while the oil expands when hot, checking an hour later will allow more to drip down to the pan from my last check, and I should have the same level as when I last checked.

Has anyone experienced something similar? Anyone found 9 liters to be more accurate? Any good advice on when to check level for most accurate readings? This oil does expand a lot when hot?

I'm reading horror stories about these engines drinking oil like there's no tomorrow, without external leaks or other obvious things (no mix with coolant, no smoke from exhaust).

I'm getting about 24-5 mpg, with full power and no obvious faults, but this is concerning to me because I think the vehicle is regenatring every 100 - 200 miles, is that normal?

Will appreciate any advice, Thanks.
I had the exact same situation with my OM642. It turned out to be piston rings.
Replacing them completely fixed the problem.

Good luck.
 

protons

New member
Sure, 2012 with 200,000 Kms and just over one litre per fuel tank fill which is around 600 km.
Thank you,
Any other symptoms? I would like to think that if oil control rings are shot, compression rings would also be and that would make other noticeable issues.
Did you notice anything else? Increased mpg? Driveability issues?
 
Last edited:

Bazookabob

Well-known member
Thank you,
Any other symptoms? I would like to think that if oil control rings are shot, compression rings would also be and that would make other noticeable issues.
Did you notice anything else? Increased mpg? Driveability issues?
Compression rings were fine. Oil control rings were seized with carbon. The oil burn destroyed the DPF.
piston.jpg
 

Bazookabob

Well-known member
How did you monitor the oil level? Checked and corrected when hot? Waited for message on dash?
Do you recall frequency of regeneration before and after the repair? Was it smoking?
I used the dip stick once engine was hot, sit for five minutes and check. The regen frequency was daily but wasn't doing the job. It was smoking but it wasn't obvious and I assumed it wasn't smoking at all. I finally noticed it at night while driving and looking through the side mirror when a car was behind me, you could see the smoke in the cars headlight beam.
I have now fixed the engine, removed the DPF, EGR, Swirl Valves and use Rotella T6 5w40. I love this engine now.
How many miles on your engine? Was it used to idle much?
 

protons

New member
I have 110 k miles on it, I'm not sure of how much idling it has done as it's new to me.

The only thing that I've been noticing is regeneration occurs every 150-200 miles, I drive 20/80 city/highway.

It's been difficult for me to monitor the oil level due to the cold climate, I'm getting inconsistent readings. If it wasn't for the frequent regeneration, i would've probably not been here.

Attached are the history of regeneration as well as live data when idling.









 

Bazookabob

Well-known member
I have 110 k miles on it, I'm not sure of how much idling it has done as it's new to me.

The only thing that I've been noticing is regeneration occurs every 150-200 miles, I drive 20/80 city/highway.

It's been difficult for me to monitor the oil level due to the cold climate, I'm getting inconsistent readings. If it wasn't for the frequent regeneration, i would've probably not been here.

Attached are the history of regeneration as well as live data when idling.









I'll bet it's regenerating so often because the burning oil is plugging it up. Mine did that as well. Where are you located?
 

Top Bottom