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I've been working on Mercedes exclusively for 20 years and 27 years total in the business, with Ferrari before that. I'm the top diagnostic tech at my shop and I fix problems that others can't. I even have independent shops as clients who bring their problem cars (all MB) to me to fix. I've worked on.. and unfortunately continue to work on... the om642 and It's garbage. The only reason they haven't been relagated to the junkyard is the emissions recall, cash payout, and 4 yr. warranty. Otherwise, owners would have parted ways with that obsolete failure of a design long ago, as the near constant out of pocket repairs, maintenance, and breakdowns far outweigh and benefit of having that engine. You're far better off with the inheritantly reliable m272 or m276 gasoline engines. There's no reason to own a om642 at this point in time unless you're one of those diesel weirdos who's stuck in the old times of 300d's. Those days are longgggg gone and they ain't coming back. The 642 is a throw away engine... Yes there are shops that SPECIALIZE in rebuilding them... Isn't that something? There are no shops specialized in rebuilding the 272 or 276 engines, because there is no demand! They don't have the massive failure rate of the 642 turd.
Your’re full of crap monkeyman. 177k on a 2013 GL350 with no impending issues. My ride is 5X smoother than my wife’s 2014 that we just ditched due to cylinder scoring @ 96k. I’ve had several 123 diesels, several 124 diesels and this x166 diesel. I agree that the maintenance requirements on the OM642 are a little more that the OM617 & OM606 but tell me what modern engine isn’t more of a maintenance hog, maybe a V6 Ford ecoboost; yeah right. Cut the oil change interval in 1/2 and run a diesel oil like T6 in it and the OM642 performs great. The only thing extra I’ve done is install a Mann ProVent 200 to patch that stupid crankcase vent system. 38k mikes since the DPF/SCR replacement and no ash accumulation in the DPF due to running “non-specified oil”.
Diabolis - feel like the nerve we have hit is yours. My 2013 R350 Diesel was sold to me as a family car - nowhere did the marketing literature suggest that the diesel version was indented for commercial use, so yea, Mercedes is to blame for selling that car with that engine.
my repairs in first 100,000 km (60,000 miles)
- some very expensive intake components because there is an embedded sensor that Mercedes doesnt make available/hard to replace : $2000. we had this repair done twice
- DEF injector: $1500 - led to dreaded 16 starts remaining
- DEF heater element : $1500
- engine has leaked oil since 60,000 km
- various sensors failed before 100,000 km resulting in check engine light - don’t even bother calling mechanic anymore for check engine light
- and that’s just the engine!
- both BLIS sensors replaced twice ($900 each!!!) due to salt corrosion because they are completely exposed under rear bumper
- exposed sharp metal edge near unprotected DRL wiring which wore through it in 50,000km shorting out DRLs - who let the student design this?
- transfer case constantly leaks fluid
I’ve owned Japanese, American, and German cars of various makes. We love the R350 because it met our needs in 2013 better than any other car (AWD, 7 seats, air suspension, towing, low roofline to allow leaving roofbox on entering house garage) and lots of luxury features for the time - BLIS, heated steering and rear seats, glass roof, quiet ride.
thata why we continue to repair it, especially now as there is really no replacement for it. But to call that design good or reliable is simply laughable - from that perspective it’s the worst car I’ve ever owned. So fool me once with the diesel engine Mercedes, but they’ve probably turned me off for life because so many things went wrong that didn’t have anything to even do with the engine, but the engine has been terrible.
I haven’t mentioned the air suspension which I’ve changed all four corners by 150,000km, and have started changing again at 250,000 km, because all air suspension systems seem inherently unreliable given the aftermarket vendors sell them for almost all makes.
So I won’t dispute the OM642 is a great engine for commercial purposes, but in Canada the R-class was not marketed as a commercial vehicle, so Mercedes should take a punch to the nose for it.
-Speedball
Originally Posted by Diabolis
Ugh... looks like we've hit a nerve here, and based on your last post it is apparent that you really are clueless. The fact that you are erroneously grouping together a "5 starts remaining" message and the OM642 engine itself says plenty about your level of knowledge. You wouldn't happen to be Tom Stephens of Stephens Service Center by any chance, would you?
I am sorry to hear your experience has been that negative - mine thankfully hasn't, and moreover I know of a VERY few instances in Canada that have resulted in catastrophic engine failures (this is based on statistical information directly from MB Canada, not a second hand account or a handful of cars that people have brought in). Unlike in the USA, 86% of all W166 and X166 MLs and GLs sold here were the 350 Bluetecs, or roughly some 32,000 vehicles. In comparison, the total number of W166 and X166 diesels sold in the US was less than half of that. Yet, the only people *****ing and moaning about the OM642 are owners from the USA that have admittedly been dealt a bad hand with their biofuel subsidies and resulting biodiesel content - for which you need to blame your government, not Mercedes - and are either too stupid or too cheap to change the oil any more often than they have to in order not to void their warranty. They also don't seem to understand that a DEF heater that dies after 5 or 6 years of freezing and thawing cycles does not make the engine crap and is technically considered a wear and tear item. The OM642 has been around since 2005, and is still being made and used today as a diesel workhorse, not just by Mercedes but also by Chrysler. Name one other modern engine that has been in production for 18 years please. And, if you think the OM642 is problematic, you really ought to have a good look at the alternatives. Unlike, say, a DEF heater, a balance shaft or intake manifold is part of the engine - and how many of those have you had to replace on the M272s that you like so much? More importantly, how many of the M272s and M276s that you've worked on have well over 250,000 miles and are still going strong?
Are the diesels the right choice for soccer moms in the USA that use them to do 20-minute grocery runs, keep putting in B20 diesel and only change the oil every 9,000 miles? Absolutely not. Are they the right choice for a vehicle that runs continuously for more than a couple of hours a day (or for that matter, 14 hours a day hauling parts) or for towing a trailer? You bet they are. If you are using the wrong tool for the job (or are using it incorrectly), it's not the tool's fault - it is yours, but you seem to be completely oblivious of that and are instead bashing the engine instead of those that are misusing it or not looking after it the way they should.
Anyway - it is apparent that you don't understand what the causes of any of the reported issues with the OM642 are and that we're not even close to having a meaningful discussion of any sort on the subject, so I guess we'll just have to disagree on this one. Thanks for your valuable input.
,,,,,,
- exposed sharp metal edge near unprotected DRL wiring which wore through it in 50,000km shorting out DRLs - who let the student design this?...
I guarantee you MB did not design it this way.
After AEM I recheck my vehicles and mechanic doing the modifications did run the wires against sharp edges of heat shield. That was just 1 of whole list of issues I had to fix after doing AEM on 4 vehicles.
Meaning job ethics with US mechanics don't really exist and once you start taking car to mechanics, that opens a chain reaction.
My OM642 in Sprinter is about 210k miles and purrs like a kitten. Only thing I had to do on it in 3 years, was oil change and once I had to add refrigerant to rear AC. Driving MB exclusively for last 25 years, rough estimate says that I spend average $30 a year on parts replacement (plus regular maintenance)
Sorry to hear about your bad luck.
I know we are off topic but the wiring was touching a big piece of aluminum (front bumper) this wiring harness was not affected by any maintenance, had to remove front clip to get at it. Trust me - it was made this way from the factory - this failure happened at 84,000 km, I’ll try and find the picture I took.
- found: you can see black foam that the wire bundle runs through, and then it rested right against that aluminum edge (not heat shield, but a big chunk of aluminum bumper) that was super sharp. Rubbed through the wrapping and wire insulation - you can see where it shorted against the aluminum. This is in the front clip of the car (the foam comes off when you remove the front clip)
- still enjoying the R-Class when it works well, just replaced failed PS pump and fluid, as well as front right bag. It’s the first PS pump at 250,000 so I think that’s ok!
Is that a clip, who suppose to hold the wires on right side?
Seeing the scratches on the bumper, I wonder if one of those incidents could pull the wires?
This is not definitely not how MB builds the car, although S**t happens and maybe the Ukrainian assemble man had a bad day.
Yeah that was poor installation. On my Ram 3500 the year I got they designed the expansion tank odd and ran the positive or negative (cant remember) battery cable on that side ran up against a sharp edge off the expansion tank. I had to cut out a C shape from the edge and put a piece of heater hose around the cable so it wouldnt rub. That was designed that way really annoying.
I have a 2009 r320 bluetec. I got it 2.5 months ago.
It had the aem recall done.
I love this car more than any other car that I have had. It's so nice to drive.
I am waiting for an adblue heater to be fixed under bluetec warranty, ETA is unknown.
However, I only spent 5800 bucks to purchase this car, so maybe that's why I feel very satisfied.
The right side mirror motor and the parktronic system do not work, but I have just left those alone.
The rear wiper arm failed and I replaced that in my driveway.
I am also very skeptical of the om642 bluetec fitted engines for passengers vehicles. I had a ml350 bluetec last year, the engine seized on the highway, it had 210k on it.
I only bought this car because it was cheap and because I am hoping to get 1800 back from the bluetec settlement. I'll probably keep it until a major component fails, but really loving the drive and the room.
There is very long thread here how OM642 engines seized due to inadequate oils put in them.
For some reason the engine makes a chemistry, where older category oils change into gelatin with consequences.
So make sure you ran 229.52 oil in them and they will last million miles... maybe with timing chain replacement.
Now with extended warranty after AEM, make sure you keep records of oil changes.
Yes I have spent many countless hours of research and worry about this problem. I see so many bluetecs seizing that are being sold on Kijiji and marketplace, it scares the daylights out of me.
My 2010 ml350 bluetec seized only 1 month after the oil change. The oil that was used was pennzoil, which was compliant with mb 229.51 but I don't think it was compliant for 229.52, which makes me wonder to this day if that's what ruined the engine. Now I exclusively use 229.52, I hope to God that this is the simple and correct solution.
So far nobody reported gelatin in Sprinter crankcase with this engine. I keep wondering if it is bigger oil pan, holding 13 l, maybe fact that Sprinters generally run long distances, so the engine is properly warmed up most of the time, or maybe the fact that in Sprinter engine replacement still makes economical sense so the owners jut put new engine in, without good checking why the old one seized.
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Very likely the combination of the first two, as well as (a) the biodiesel content where they are being driven (it is the higher lubricity of biodiesel that makes it past the piston rings and into the crankcase, especially during DPF regen cycles), and (b) the fact that commercial vehicles are generally regularly serviced. If the biodiesel content is low a lot less fuel gets by the piston rings and ends up in the crankcase, and also because the engine is hot for longer periods of time it does have a chance to fully evaporate instead of solidify when combined with moisture (which also fully evaporates).
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
In response to @Chrome988's post, MB 229.52 approved oils have considerably better oxidation stability over MB 229.51, which is essential if you live in a state where the diesel pumps put out ~20% biodiesel content. If you're in the US with all of the state-level biofuel subsidies, incentives and mandates, it makes a huge difference. If you're in Canada where the biodiesel content is (still) limited to no more than 5%, not so much as oil oxidation is not as big of a challenge (assuming all other things being equal of course).
In response to @Chrome988's post, MB 229.52 approved oils have considerably better oxidation stability over MB 229.51, which is essential if you live in a state where the diesel pumps put out ~20% biodiesel content. If you're in the US with all of the state-level biofuel subsidies, incentives and mandates, it makes a huge difference. If you're in Canada where the biodiesel content is (still) limited to no more than 5%, not so much as oil oxidation is not as big of a challenge (assuming all other things being equal of course).
Clicked off another 5,000 miles, I did run a OCI of Valvoline Premium RESTORE just as a carbon preventative. Might be snake oil but it is doing good things for the ISX engines so what could 5,500 miles hurt?? I replaced the 19” wheels with factory 20” wheels so I could fit a set of Michelin 285/50/20 defender LTX tires, man what a great ride!! I have driven it 700+ miles in 3 days and I wish I had made the this tire change on the last set. Vehicle is doing great, mileage is ~182k. It’s gotta last another 75-80k so I can get my money’s worth out of the tires & wheels LOL.
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Originally Posted by olesouthernboy
Clicked off another 5,000 miles, I did run a OCI of Valvoline Premium RESTORE just as a carbon preventative. Might be snake oil but it is doing good things for the ISX engines so what could 5,500 miles hurt?? I replaced the 19” wheels with factory 20” wheels so I could fit a set of Michelin 285/50/20 defender LTX tires, man what a great ride!! I have driven it 700+ miles in 3 days and I wish I had made the this tire change on the last set. Vehicle is doing great, mileage is ~182k. It’s gotta last another 75-80k so I can get my money’s worth out of the tires & wheels LOL.
AFAIK that oil was developed by Valvoline in conjunction with Cummins engineers to clean out an engine that is suffering from a specific problem with excessive carbon buildup on the rings on some ISX engines, which would cause the rings to stick and the oil consumption would go through the roof (there was a Cummins TSB specifying how and when to use this oil to clean out an engine that is suffering from this problem). It is not designed to be used as a regular HDEO oil, much less in a Mercedes OM642. I would not have taken the chance, but you're obviously braver than I am.
Michelins are great tires... easily the best street tires on the market now and probably also the best bang for your buck once you take into account that they wear considerably better than any other brand (I do not necessarily mean that they last longer in absolute terms, only that they wear and grip more uniformly throughout their life unlike pretty much anything else). Michelins are all I use on all of my street cars (both summer and winter tires), and we recently put them on for the first time on two of the Sprinters as well.
P.S. Found the info on the Valvoline Premium Blue Restore Oil - PDF attached for your reference.
AFAIK that oil was developed by Valvoline in conjunction with Cummins engineers to clean out an engine that is suffering from a specific problem with excessive carbon buildup on the rings on some ISX engines, which would cause the rings to stick and the oil consumption would go through the roof (there was a Cummins TSB specifying how and when to use this oil to clean out an engine that is suffering from this problem). It is not designed to be used as a regular HDEO oil, much less in a Mercedes OM642. I would not have taken the chance, but you're obviously braver than I am.
Michelins are great tires... easily the best street tires on the market now and probably also the best bang for your buck once you take into account that they wear considerably better than any other brand (I do not necessarily mean that they last longer in absolute terms, only that they wear and grip more uniformly throughout their life unlike pretty much anything else). Michelins are all I use on all of my street cars (both summer and winter tires), and we recently put them on for the first time on two of the Sprinters as well.
P.S. Found the info on the Valvoline Premium Blue Restore Oil - PDF attached for your reference.
Yes sir you are 100% correct on the PBR oil. I studied it, learned about and how they are using a HEAVY dose of a specific group V ester then a PAO plus their add pack to slowly remove the carbon in the ISX engines. I used their recommendation of a 5k OCI (gas engine OCI) instead of a 10k+ OCI. The OM642 seemed to like that oil (ran a little quieter) although I’ll probably never use it again. I did switch to Delvac 1 ESP from T6 after you (I believe it was you anyway) twisted my arm into doing some reading. I’m happy to report that that I got great mileage coming back from a long trip although it was not on the interstate. When I was about 45 miles from home I reset the meter just to see what it would get and I thought 34mpg was respectable. My speed was 55-60mph. All in all I have confidence that this thing will make 300k mechanically. Oh yeah, on the interstate I’m getting high 400’s between regens and when I’m in town it’s getting ~350-375 between regens.
Next project is replacing lower front control arms, bushings are toast, rear ones will be shortly after that. Any suggestions on other suspension parts while I’m in there?
I'd probably replace the driveshaft / CV joint boots if you haven't already, and get a good alignment afterwards.
Thanks for the thoughts! Are they not very reliable? The ones on my 1983 W123, 1995 W124 & 2002 W163 (320) are still rocking along and in good shape. I have heard of the front diff’s going bad, not super often but does seem to happen. I do not tow with this SUV and the fluid is changed every 30k. I have replaced the transfer chain about 50k miles back. Although the car was 100% dealership maintained until I got it they overlooked the transfer case fluid, one of the easiest fluid changes on the thing. When I removed the drain plug I might have gotten a thimble full of ATF out of it. I have been using Valvoline synthetic ATF with about 5ml of MoS2 added. The case was pretty nasty so I’ve changed the fluid about 4-5 times to clean it back up. After the first few changes the the drained fluid is nice & clean.
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Originally Posted by olesouthernboy
Thanks for the thoughts! Are they not very reliable? The ones on my 1983 W123, 1995 W124 & 2002 W163 (320) are still rocking along and in good shape. I have heard of the front diff’s going bad, not super often but does seem to happen. I do not tow with this SUV and the fluid is changed every 30k. I have replaced the transfer chain about 50k miles back. Although the car was 100% dealership maintained until I got it they overlooked the transfer case fluid, one of the easiest fluid changes on the thing. When I removed the drain plug I might have gotten a thimble full of ATF out of it. I have been using Valvoline synthetic ATF with about 5ml of MoS2 added. The case was pretty nasty so I’ve changed the fluid about 4-5 times to clean it back up. After the first few changes the the drained fluid is nice & clean.
It depends on the age and where you are located (climate-wise). Rubber tends to get harder and thus more brittle at lower temperatures, so if you keep the car outdoors in some places in Canada where the temperatures dip to -30 C overnight, they tend to fail earlier. If you're in a warmer place, I'd just have a good look at the rubber. If you don't see any surface cracking or deterioration you're good... check them again in another 3-5 years.
The transfer case fluids are not scheduled to be replaced as part of regular maintenance, i.e. they are filled for life now that cars are "perishable" goods, which I think is a myth. While I also haven't read of many diffs failing, I did change the fluid on mine after 5 years (mileage at the time was ~60,000 kms)... if you think about it, the front differential in particular is "in use" all the time as every time you turn, the front wheels travel different distances (plus I regularly tow one of the race cars with the ML). Both diffs use 75W-85 hypoid gear oil (MB 235.7 IIRC), not ATF though - or are you talking about the transmission, not the diffs?
Very likely the combination of the first two, as well as (a) the biodiesel content where they are being driven (it is the higher lubricity of biodiesel that makes it past the piston rings and into the crankcase, especially during DPF regen cycles), and (b) the fact that commercial vehicles are generally regularly serviced. If the biodiesel content is low a lot less fuel gets by the piston rings and ends up in the crankcase, and also because the engine is hot for longer periods of time it does have a chance to fully evaporate instead of solidify when combined with moisture (which also fully evaporates).
are you using the term lubricity in place of viscosity?
how would the lubricity of a fuel mean it gets past the rings?
does it stick to the liners and get dragged down by the scraper ring in higher amounts? Does more of it slip past the injector nozzle?
this is a new one for me, and I’ve worked with diesels my whole life.
regarding the OM642 as a whole. I think it’s a great little motor and it’s nice and punchy for their size, but they are trash.
Mine had stretched a [duplex] timing chain by around 19mm when I changed it last year in a 2010 ML350.
120k miles and I drive the car for well over an hour without stopping every day, coming and going from work.
it was slapping like a MF on cold startup.
Unacceptable in a premium vehicle like this.
I had switched to driving Mercedes’ after having BMW’s for my whole life, because I was sick of fixing BM’s… but this foray into Merc ownership has been enough to put me off owning another one.
apart from the chain I’ve also had a complete failure of the command system resulting in a permanent “anti theft active” message, and the air conditioning compressor failed, and a coil spring snapped (while it was parked) necessitating replacing all four, and the fuel lines rotted out above the fuel tank, and the handbrake assembly completely disintegrated inside the hub at the back.
it’s every bit as bad as any BMW I ever had.
I have a Toyota Prado with 238k miles on it and all it ever needed was injectors because they literally wore out due to the volume of diesel that had passed through them. That’s it.
when I replace the Merc it will be with a Prado, Landcruiser or RX450h. I will be quite content driving something a little less fancy in exchange for it having to deal with these types of failures.
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Originally Posted by SeanyF
are you using the term lubricity in place of viscosity?
how would the lubricity of a fuel mean it gets past the rings?
does it stick to the liners and get dragged down by the scraper ring in higher amounts? Does more of it slip past the injector nozzle?
this is a new one for me, and I’ve worked with diesels my whole life.
regarding the OM642 as a whole. I think it’s a great little motor and it’s nice and punchy for their size, but they are trash.
Mine had stretched a [duplex] timing chain by around 19mm when I changed it last year in a 2010 ML350.
120k miles and I drive the car for well over an hour without stopping every day, coming and going from work.
it was slapping like a MF on cold startup.
Unacceptable in a premium vehicle like this.
I had switched to driving Mercedes’ after having BMW’s for my whole life, because I was sick of fixing BM’s… but this foray into Merc ownership has been enough to put me off owning another one.
apart from the chain I’ve also had a complete failure of the command system resulting in a permanent “anti theft active” message, and the air conditioning compressor failed, and a coil spring snapped (while it was parked) necessitating replacing all four, and the fuel lines rotted out above the fuel tank, and the handbrake assembly completely disintegrated inside the hub at the back.
it’s every bit as bad as any BMW I ever had.
I have a Toyota Prado with 238k miles on it and all it ever needed was injectors because they literally wore out due to the volume of diesel that had passed through them. That’s it.
when I replace the Merc it will be with a Prado, Landcruiser or RX450h. I will be quite content driving something a little less fancy in exchange for it having to deal with these types of failures.
No, not viscosity - I do mean lubricity. It's a property of how slippery the fuel is and how much of it gets past the piston rings (it has nothing to do with the injectors). Biodiesel has higher lubricity than dinosaur juice diesel so more of it ends up in the crankcase.
The biggest killer of timing chains (both the earlier double row and the later single row ones) is carbon - soot - suspended in the oil. So, timing chain failures again boil down to long oil change intervals. If you were only changing the oil only as often as the recommended OCI, you have your culprit. The fact that the prescribed OCI by Mercedes was far too long for some states where the government changed the game and decided to subsidize corn and soybean farmers and the diesel pumps started spewing out B20 instead of the maximum B5 that the engines were designed and built for is technically not Mercedes' fault. We do UOAs every 8K kms and usually go 16K kms (10K miles) or 24K kms (15K miles) on the Sprinters, but we only have a maximum B5 content. None of the five Sprinters we have or my ML have had timing chain issues - and the Sprinters have *way* over 120K miles.
As for the rest of the MLs and GLs, all of the ones sold in NA were built in the Tuscaloosa, Alabama plant after Daimler's divorce from Chrysler - so yes, they are indeed crap compared to luxury vehicles that were built in Germany or Japan and imported here. That's unfortunately par for the course and not in any way unexpected. While Mercedes managed to eventually improve quality control at that specific plant over the next few years after they completely revamped literally every single process on every production line, the stuff they were making back then - and to a somewhat lesser extent, the stuff they are still making now - was/is indeed garbage by German or Japanese standards.
No, not viscosity - I do mean lubricity. It's a property of how slippery the fuel is and how much of it gets past the piston rings (it has nothing to do with the injectors). Biodiesel has higher lubricity than dinosaur juice diesel so more of it ends up in the crankcase.
The biggest killer of timing chains (both the earlier double row and the later single row ones) is carbon - soot - suspended in the oil. So, timing chain failures again boil down to long oil change intervals. If you were only changing the oil only as often as the recommended OCI, you have your culprit. The fact that the prescribed OCI by Mercedes was far too long for some states where the government changed the game and decided to subsidize corn and soybean farmers and the diesel pumps started spewing out B20 instead of the maximum B5 that the engines were designed and built for is technically not Mercedes' fault. We do UOAs every 8K kms and usually go 16K kms (10K miles) or 24K kms (15K miles) on the Sprinters, but we only have a maximum B5 content. None of the five Sprinters we have or my ML have had timing chain issues - and the Sprinters have *way* over 120K miles.
As for the rest of the MLs and GLs, all of the ones sold in NA were built in the Tuscaloosa, Alabama plant after Daimler's divorce from Chrysler - so yes, they are indeed crap compared to luxury vehicles that were built in Germany or Japan and imported here. That's unfortunately par for the course and not in any way unexpected. While Mercedes managed to eventually improve quality control at that specific plant over the next few years after they completely revamped literally every single process on every production line, the stuff they were making back then - and to a somewhat lesser extent, the stuff they are still making now - was/is indeed garbage by German or Japanese standards.
thanks for the follow up, I appreciate the response.
regarding the lubricity, please can you tell me how higher lubricity means more fuel ends up in the crank case?
The fuel that goes in the cylinder gets mostly burnt, and in my experience the only things that can result in fuel in the oil are a lot of short trips where the piston hasn’t had enough time to expand fully and there’s a path to the sump past the piston because the gap between it and the liner is bigger. That and over fuelling.
Over fuelling turns up in many other ways though, so if you were over fuelling you’d have lots of other symptoms to let you know.
I have also seen it happen through raw fuelling (failed injector) and a failed seal in an injection pump too, which allowed fuel to enter the crankcase through the drive shaft for the HP pump where the drive gear was.
im not saying you’re wrong, I’m just saying I haven’t come across this phenomenon before and am interested in it.
id like to know the specifics of how it happens, more than just a simple statement of:
high fuel lubricity = fuel in crankcase/sump/oil.
can you talk us through it? i.e. how high fuel lubricity causes the fuel to make it into the oil?
regarding the ML, mine is in Europe where it has been all it’s life. In my country we don’t use as much biodiesel as the states at B7.
however it was B5 for a few years before that and B0 for the first few years of my trucks life.
I change my oil every 5k miles so less than half the suggested interval. Yet my chain was stretched by that amount and the timing was way off.
The OM642 is just not a good motor for durability, but it is a good motor for actually using day to day. I like driving the car, but I dislike the car overall.
regarding the prevalence of the timing chain issue in OM642’s in general, particularly the sprinter, it is massively widespread. If you’ve had 5 vehicles with no issues then I’m delighted for you, that’s really awesome, but that is statistically very rare.
There’s even a guy running a YouTube channel showing how to do the chain in the OM642 and he specialises in doing it in the sprinter. I actually bought the tool I used to hold the chain on the sprockets whilst feeding in the new chain from him.
Here’s his channel:
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
The fuel sticks to the cylinder walls and gets past the piston rings during the compression and the exhaust cycles. There's no other way for the fuel to end up in the sump. Your windshield wipers can nicely clean the windshield of water when it rains. However, if a car ahead of you is spraying oil and some of it ends up on your windshield (which occasionally does happen during racing for example), how effective are the windshield wipers in clearing it?
Google "biofuel lubricity and oil dilution" and you'll get tons of material on the subject of what happens and what it does to the oil . Here are three of the top five Google results that explain what happens to the oil.
The fuel sticks to the cylinder walls and gets past the piston rings during the compression and the exhaust cycles. There's no other way for the fuel to end up in the sump. Your windshield wipers can nicely clean the windshield of water when it rains. However, if a car ahead of you is spraying oil and some of it ends up on your windshield (which occasionally does happen during racing for example), how effective are the windshield wipers in clearing it?
Google "biofuel lubricity and oil dilution" and you'll get tons of material on the subject of what happens and what it does to the oil . Here are three of the top five Google results that explain what happens to the oil.
thanks for another follow up. I’m enjoying this back and forth and appreciate you taking the time.
ok, so we’re more or less on the same page then regarding the lubricity.
in my first post I asked if it was caused by it sticking to the liner walls, which from the sounds of it it is. It gets scraped down by the scraper rings in larger amounts.
I guess the only other part then is why is there enough of it in the cylinder to start with that it’s sticking to the liner instead of getting burnt? That’s not normal at all.
I would wager that the lubricity also means that more of it slips past in the injector meaning a slight excess of fuel in the chamber. I would assume that the metering of fuel in the injector is done within a certain range of properties, e.g. viscosity and lubricity etc. that would have been programmed when B20 wasn’t around yet.
I wonder if a software update to tell the car that to meter less fuel per stroke and retard the injection quantities accordingly could solve that problem.
you’d imagine that excess fuel in the chamber would result in a lot of other problems too, like after burning etc.
interesting one for sure. I’ll read up on it. It’s new to me because we don’t have the same level of biodiesel as you guys do.
regarding the timing chain stretching, when your doing the oil analysis are you seeing high levels of carbon build up in the oil in general? Is that what you’re using as a marker for when to change the oil?
we run caterpillar 3516’s at work and those have a centrifugal filter to take the carbon out. In theory you don’t have to change the oil till a sample comes back bad, but we do it at 1000hr intervals.
10-28-2022, 11:13 PM
LOL.
into doing some reading. I’m happy to report that that I got great mileage coming back from a long trip although it was not on the interstate. When I was about 45 miles from home I reset the meter just to see what it would get and I thought 34mpg was respectable. My speed was 55-60mph. All in all I have confidence that this thing will make 300k mechanically. Oh yeah, on the interstate I’m getting high 400’s between regens and when I’m in town it’s getting ~350-375 between regens.
