C5DRVR

There definitely is more to the story here and if I was one of the vehicle owners here I would want to understand why this happened.

I am speculating here but I suspect the new diesel emission requirements and emission systems have a lot to do with the sludging. Extremely high Exhaust Gas Recirculation rates combined with the diesel exhaust filter regeneration strategy MB uses could be the culprit here. It is well acknowledged that short drives with interrupted diesel exhaust filter regenerations introduces diesel fuel into the engine oil via the egr.
Ford and GM diesels have engine management strategies and driver alerts to help deal with this and I am surprised that MB does not. If they do, I am not aware.

nelbur

I don't understand this statement at all. Isn't the EGR added to the intake air and introduced into the combustion chamber where the injected diesel fuel is burned. How would this cause fuel to get into the engine oil to any greater extent than normal blow by?

C5DRVR

The heavy soot loading by the egr and over fueling done periodically to accomplish regeneration / burn off of the diesel particulate filter is allowing a very rich mixture in the combustion chamber at times. It frequently gets past the piston rings. Fords answer is to measure the increase of oil capacity and will call for an oil change. GM's answer has been to add a extra fuel injector in the exhaust stream (downstream of the egr) to avoid oil dilution. Here is an intersting article on EGR and the dilemmas caused by the new emmission standards.

http://www.machinerylubrication.com/...diesel-engines

This is from diesel power magazine:
Oil Dilution
One negative habit of the 6.4L is its ability to make oil. That is to say fuel slips past the piston rings and accumulates in the crankcase. It’s especially common in DPF-equipped trucks that see more regeneration cycles. Remember, the 6.4L’s regeneration cycle uses a post-injection event to introduce extra fuel during the exhaust stroke. In a perfect world, 100 percent of that fuel vaporizes and travels downstream to the catalyst (which serves as an incinerator for accumulated soot). But in reality, not all fuel vaporizes during the post-injection event, and the leftover fuel latches onto cylinder walls and squeezes past the piston and rings, and into the crankcase. We know one 6.4L owner who drained 6 gallons (24 quarts) of oil during an oil change—3¾ gallons (15 quarts) would’ve been normal. That’s nearly a 60/40 mix of oil to fuel circulating throughout the crankcase.

Mercedes uses the same post injection event as Ford.

ImInPA

Then why are the millions of Bluetec Sprinter vans not experiencing this? I agree that there is more to this story than has been presented.

C5DRVR

Most of them do but not to a catastrophic degree. Our answer in our small fleet of sprinters has been to change the oil more frequently as insurance. I am a fan of MB diesels however I wish MB would have adopted the extra injector strategy. I believe the long term durability we enjoyed by buying a diesel in the past has been greatly compromised to meet emission standards.

Carsy

Interesting comments. Thanks.

I will continue changing my oil at 10,000 Kilometres.

isstay

Mercedes engine will warn you if oil level raises. The problem in all cases is not oil dilution but oil quality degradation and break down.

N_Jay

Do the CDIs also have a high oil level warning?

houseofdiesel

I doubt it, they don't seem to have a working low level sensor either!
Sprinters have fewer reported problems because they are driven long distances or never even shut off all day just run and run. Service vehicles get driven for the most part.
Most of the sludging issues are from short driving distances, bio diesel use, lack of oil changes or improper servicing (whether wrong oil or not draining it all).

N_Jay

Well I know my low oil light works.


I am stuck in Bio-Diesel hell (IL), so I avoid short trips, fill up out of state whenever I can, watch my oil level, and change it every 10K miles.


That's my plan for now.

nelbur

Diesel oils typically have high levels of detergents and dispersants to keep the engine clean of soot. If I had one of these problem engines I would use an oil designed primarily for diesels, and not a multipurpose oil with a hard to find diesel rating. I likely would also change oil and filter much more frequently, like every 5000 miles. I have used many oils in my diesels over the past 20 years or so and have found Rotella oil by Shell to be a fine diesel oil.

I have been using Mobil 1 in my E 300 D since I bought it about 7 years ago. I recently used Rotella T6 synthetic and found that the parts visible through the oil filler hole were noticeably cleaner after the T6 than they were before. I don't see how an engine could sludge up if one used a good diesel oil changed frequently, but of course I don't understand why they sludge up in the first place.

N_Jay

I don't think Rotella T6 has a 226.51 rating (yet), although Shell says it exceeds 226.51.


All the newer CDI and BlueTech require 226.51 spec oil.

isstay

Yes they do.

http://mercedesforum.com/forum/merce...-2005-a-42796/

Rotella T6 has 228.31 approval but probably can be in 228.51 too, since this is Low SPAsh oil. CDI can run on 229.3/229.31 or 229.5/229.51 where "1" indicates Low SPAsh oils. BlueTEC and everything else with DPF requires .51 oil but can use .31 also since both groups contain almost same oils.

Carsy

List of 229.51 Low SPAsh multigrade service engine oils (Specification 229.51)

http://bevo.mercedes-benz.com/bevolisten/229.51_en.html

N_Jay

'08 GL320 CDI specified 226.51 oil only.


Shell says the T6 " . . . exceeding the MB 228.51 requirements in the . . . OM 611LA, OM 501LA and OM 646LA engine tests. "

But does not show 226.51 on is certification list. (Wonder exactly which test they fail)

isstay

Are you sure is 226.51 and not 229.51? If is 226.51 you will have big problem finding oil (only 7 on the sheet).

http://bevo.mercedes-benz.com/bevoli...nt_action=show

Rotella T6 brochure states 228.31 (not LowSPAsh oils), but also states that the oil is good for cars with DPF, more like 228.51 sheet.

http://s02.static-shell.com/content/...6-brochure.pdf

All those OM xxxLA tests correspond to each engine they test the oil on it when developing the oil to meet bore polishing standarts. Simply enough they did not test one on your car OM 642, thus not on the list.
611 and 646 (think Sprinters as target market) are 4 cylinder diesel for cars and vans, 501 is V6 but is 12 liters in displacement.

http://www.cectests.org/public/info_...cec09_1993.pdf

DUTCH

Actually the specs are 228.51, 229.31 or 229.51.

The attached table is from the 2014 ML350BTC Owners Manual.

Also, notice how carefully the wording in the MB Spec is used:

Here's the link to the English language 229.51 Spec Sheet. Lots and lots of approved oils.

http://bevo.mercedes-benz.com/bevolisten/229.51_en.html

N_Jay

You are right.


Sorry, it is 229.51.


Either way, looks like Rotella T6 does not make the grade.

houseofdiesel

The sludging issue is not likely due to the oil spec, but fuel and driving conditions. They are not reporting plugged DPF problems.
I wonder if something inside the engine is letting go or if its just oil related, like the Audi/VW V6 engines would loose pieces of plastic of the camshaft tensioners that would engine up in the oil pump pickup screen. Plastic inside engines is never going to last very long, yet it is used more and more. Their 1.8T engines would oil sludge, this was a problem with the crankcase breather clogging up/freezing and causing all sorts of issues, in extreme cases the oil pump screen would clog with crap. It is possible that the crankcase breather was an issue on these engines but nobody cares to investigate, or it could be fuel. MOst cases so far point the finger very clearly at the customer very quickly withtout real diagnostics/tear down.

Dima1725

I have exactly the same situation, and they are also saying the mechanic is lying and the filter was not changed. Don't know what to do???

N_Jay

Have the dealer put that in writing, then file against the mechanic.

skromfols

N Jay, great idea. Then after you file against the mechanic he can file a suit against Mercedes. Everyone wins.

N_Jay

I doubt there is a suit against MB.


But if the mechanic was negligent (or fraudulent) then his business insurance should pay.


If he wasn't it puts MB on the hot seat to explain how they knew the filter was not changed?


If they were negligent or fraudulent in providing that information to you, then you take that upstream with MBUSA.

skromfols

If they put it in writing that the sludge problem was caused by the mechanic lying about changing the filter he certainly would have a law suit against them.

sbailey48

I've read recently that MB & VW are starting to sell new diesels in Ill. and that they have decided to recommend more oil and filter changes to ward off warranty claims. This is due to the Bio Diesel that is mandated. You might want to change oil more often or at least the filter. Filters are easy and cheap, Mahle's going for $5 at Rock Auto.