Most people find this article after some major problem with their Mercedes-Benz BlueTec diesel. Still others are trying to research a potential new or used purchase.  Other owners have followed a link from one of the many Mercedes related owner’s forums.  I originally wrote the article as a way to explain BlueTec diesel maintenance to my local customers.  As time passed I began to hear from BlueTec owners around the world.  There isn’t a day goes by that I don’t hear from a BlueTec diesel owner.  Saying there’s been a lot of needless heartache would be an understatement.  As I talk to all these people I realize I need to improve the content of this article.  This is a hard subject to effectively communicate.  I’m constantly coming across something new and I need to add it to the article.  People will read something on a Forum and ask a question.  When I look at what they’re referring to, it’s from 5 years ago and no longer applies.  I worked for Mercedes-Benz as a Mechanic, Shop Foreman, Instructor, and a Service Manager for 50 years.  I retired in 2017. This article is strictly my opinion.  I have no connection to Mercedes-Benz or their dealers.  My intention is to help explain this engine and avoid its problems.  I be the first to admit this is an endless work in progress.

When Mercedes-Benz introduced the OM642 V6 diesel in 2008 everyone was blown away by the new found power.  Mercedes had a Diesel engine that was just as fast as many of their gas engines.  Automotive magazines thought the Diesel engine was reborn.  Mercedes own mechanics thought they were witnessing the end of the gas engine.  Shortly after the OM642 V6 diesel, Mercedes brought out the OM651 four cylinder diesel.  After the euphoria wore off mechanics began to realize this was not the same diesel they had known for the last 60 years.  Suddenly dealer mechanics didn’t want anything to do with these engines.

I’m only going to deal with the hard problems in this article.  If you want to know about the vehicle features or production information, you can look that up on an automotive website. No doubt you already know there is not much technical information about BlueTec problems.  After a few years Mercedes dropped the BlueTec’s from their passenger cars.  Currently the OM642 diesel only comes in the immensely popular North American built Sprinter.  I still hear from a few passenger car owners, but most have given up. The cost of repairs is too much for most people. On the other hand, Sprinters are one of Mercedes most popular models.  Sprinter owners tend to have a love hate relationship with their Sprinter.  While Sprinters really hold onto their resale value, they can be expensive to maintain.  Sprinters drive better than any other big van.  Fuel economy and safety features are second to none.  On the flip side, it can be hard to find a competent mechanic.  Routine maintenance is confusing and inconsistent.  Owners argue endlessly about something as simple as the correct oil and when to change it.  One dealer bends over backwards for their customers while the next dealer does just wants to fight.

The engine and emission systems are virtually identical for the passenger cars and the Sprinters. Since Sprinters are currently in production I’ll focus on them.  Whether it’s work of pleasure, Sprinter owners have a lot in common.  They both have a lot invested and can’t just walk away from them when they have problems.  Work Sprinters are packed with all the stuff the owner needs for their business.  They can’t just get a loaner and leave the Van in the shop for a week. The RV owner is in the same boat.  These owners bought it to travel.  They can’t just set in a dealer for a week waiting to diagnose a Check Engine light.  I’ve found that most Sprinter owners will actually do the preventive maintenance if they only knew what it was.  For some reason, Mercedes has always had a problem with plainly explaining the maintenance.  Every year Mercedes Marketing Department comes up with some new maintenance plan.  When owners contact Mercedes-Benz Customer Service and them to clarify the discrepancies, they tell the owner to contact their dealer.  When owners ask their dealer a hard question about the maintenance, the dealer says to contact Customer Service.  For example, Mercedes published Service Bulletin “GI01.10-P-056315” about “Oil Slugging in OM642 engines”.  The bulletin tells Mercedes dealers how to handle oil related OM642 engine failures.  That sounds important.  So what exactly is Mercedes talking about?  When dealers install the new engine, the bulletin says the dealer should “only use oils from the specification MB229.52 when changing the oil”.  The bulletin is talking about oil related engine failures.  Most owners think this is important and would like a clear and unambiguous answer about the correct oil for the engine.  On the Mercedes-Benz website for approved oil, “”, Mercedes specifically says “Labels referring e.g. to MB229.51 don’t have an approval of Mercedes-Benz”.  That’s not what it says in the Owners Manual.  I don’t want to get overly technical about the oil for a BlueTec diesel.  But it’s a subject that’s debated endlessly on all of the owner’s forums.  Mobil One 5W/30 ESP is the official factory recommended oil for BlueTec diesels.  It’s the oil Mercedes-Benz puts in new engines at the factory.  If you go to Exxon Mobil’s website and look up the Product Data sheet for this oil it will tell you the actual approvals this oil has.  The approvals come from three major oil rating agencies.  JASO (Japan), ACEA (Europe) and API (America).  Between these three, they independently test every oil in the world.  Mobil One 5W/30 ESP doesn’t come close to meeting the proper Turbocharged diesel oil ratings for JASO and ACEA.  Mobil One 5W/30 ESP doesn’t even have an API diesel rating.  API says Mobil One ESP is only approved for gas engines.  JASO and ACEA rate Mobil One ESP as a light-duty diesel oil for non-Turbocharged diesels.  When a owner presses Mercedes about these inconsistencies, Customer Service gets frustrated and makes vailed threats about voiding the warranty if a non-approved engine oil is used.  Hello… that’s why owners contact Customer Service in the first place.  The highest JASO diesel rating is DH-2.  The highest ACEA diesel rating is E9.  The highest API diesel rating is CK-4.  There are lots of diesel oils that meet the highest ratings and also meet the Mercedes ratings.  Once you have a oil that meets all of the highest ratings, then you look at the NOACK Volatility and the Viscosity Index. The lowest NOACK Value is the best.  The highest Viscosity Index (VI) is the best.  In the same oil, 3.7% is the lowest NOACK Value I’ve found with a Viscosity Index of 151.  There are higher Viscosity Indexes but the NOACK Value also increases.  I think the lowest NOACK Value is the most important.  NOACK measures how an oil withstands extreme temperatures and doesn’t boil away. I know this is tedious, but it explains many of the problems.  There is a lot more to oil than this. But this is a good starting point for zeroing in on the best possible oil for a BlueTec diesel.  The advertising nonsense on the oil bottle tells you nothing.

The OM642 BlueTec diesel has been in production for over twelve years.  By now there should be plenty of technical information about them, so where is it?   You’ll find a little owner’s forums. YouTube also has some repair advice.  They both tend to dwell on a few common repairs.  They never get into why the repairs were needed in the first place.  They don’t peel back the layers of underlying issues that caused the problem.  I’ll be the first to admit that it’s hard to tie all the different problems into a neat explanation.  I’m often ask why I keep editing this article. I constantly struggle with the best way to explain this engine and emission system.  The last thing I want to do, is add to the confusion.

Diesel engines are inherently dirty.  Practically every problem with a BlueTec engine has its roots in the emissions system.  Soot is the most obvious emissions problem from a diesel but it’s not the only problem.  Soot is the black smoke you see in diesel exhaust.  Soot is also what turns diesel oil black.  Engineers designed the Diesel Particulate Filter (DPF) to capture the soot as it moves through the exhaust.  How and where you drive determines how fast the DPF fills with soot. Pressure sensors tell the engine’s computer (ECU) the DPF is full of soot.  Then the ECU injects extra fuel to increase the exhaust temperature to 1600F.  The extreme heat burns off the soot trapped in the DPF.  This self cleaning process is known as “regenerating the DPF” or “regeneration”.  On average, the DPF regenerates every 300 miles.  If you drive short trips in cold weather, the DPF will need to regenerate more frequently.  However, it takes about one hour in cold weather for the DPF to complete the regeneration.  If you don’t run the engine for a hour at freeway speeds, the DPF clogs up.

It’s the process of regenerating the DPF that causes so many other problems.   During regeneration not all of the extra diesel fuel is burned.  Some of the extra fuel washes past the piston rings and into the crankcase oil.  Mercedes calls this “fuel accretion”.  Diesel fuel is obviously not very good for the engine oil.  If you use B20 biodiesel it makes the problem much worse.  If you drive in freezing weather, it makes the problems much worse.  Short trips in city traffic, it makes the problems even worse.  You can’t drive a BlueTec like a Gas engine.  If you do, you’ll need to greatly increase the maintenance.

How and where you drive determines how much diesel fuel will go into your crankcase oil.  If you make short trips in cold weather and shut the engine off before the engine has time to regenerate, expect to have a lot of problems.  The engine never gets hot enough to regenerate the DPF and the oil also never gets hot enough to burn off the condensation that naturally accumulates in the oil.  Freezing temperatures will cause the condensation to freeze.  Frozen moisture in the Crankcase Ventilation system acts like sand in your oil.  Frozen moisture is very hard on the Turbocharger.  Frozen moisture in the crankcase oil starves the engine for oil in cold weather.  Mercedes tells owners they can go 20,000 between oil changes.  Dirty oil will have a lot of condensation and diesel fuel mixed in the oil.  When the temperature drops below freezing the oil becomes a frozen glob.  You should always change the oil before the start of freezing weather. You should also use a Block Heater to keep the oil from freezing.
Soot is also abrasive.  The more soot in the oil, the more wear you can expect.  Replacing the oil filter every 2500 miles is a simple way to remove the soot.  As more diesel fuel washes past the piston rings it causes more hot crankcase oil vapor to enter the Turbo, EGR, Swirl Flaps and the DPF.  As the soot builds up in the DPF the ECU ask for more frequent regenerating of the DPF. That dumps even more fuel into the crankcase.  The cycle feeds on itself and makes the problem even worse.  If you make short trips in cold weather, you should change the oil every 3,000 miles and ask for a manual regeneration of the DPF.  Mercedes even published a Service Bulletin (SI00.20-D-0029A) about this, but the Owners Manual still says you can go 20,000 miles between oil changes.

Mercedes-Benz explains Regeneration of the DPF in one of their Service Bulletins.  “The normal regenerating intervals of the BlueTec DPF (the driving distance between two regeneration periods) is 130 miles of City driving, and 320 miles of Highway driving.”   The problem is, very few people only drive in the City or the Highway.    “The duration of a regeneration period generally lies between 15 and 25 minutes.” (The regeneration of the DPF takes 15 minutes if you’re on the Highway and 25 minutes in City traffic.)  It takes the engine about 30 minutes to warm-up enough to begin the regeneration. If you only make short trips in stop & go traffic it can take up to an hour of city driving before you’ll complete a regeneration of the DPF.  Thirty minutes to warm up the engine and another 25 minutes to complete the regeneration.  The colder the weather the longer it will take.   If you shut the engine off before the regeneration is complete, all that extra fuel was a complete waste.  You got a load of diesel fuel into your crankcase and nothing to show for it.   If you keep making short trips, you’ll eventually have a crankcase full of diesel fuel and a clogged up DPF.  On the other hand Freeway driving helps the regeneration go more quickly and with less frequency.  If you kick it into passing gear while going up a hill the DPF is in heaven.  Vehicles primarily driven on the Highway in warm weather will have far fewer problems.  This is only a tiny part of what’s actually happening but should help explain why some owners have more trouble than others.  But even with this simplified explanation there are plenty of mitigating factors such as: How old is the ECU software?  What type of oil is used?  When was the oil last changed? Has the Oil Separator been replaced?  How dirty is the air filter?  The list goes on and on.  This is why one owner says he never has any problems and his neighbor is calling a salvage yard.

How can Mercedes-Benz realistically tell every BlueTec diesel owner they can go 20,000 miles between oil changes?  How can they tell every owner to use the same Mobil One 5W/30 ESP oil? According to Mercedes it doesn’t matter where you live or how you drive.  The guy in Chicago who drives 10 minutes to work in January gets the same oil and service intervals as the guy who tows a 7,000 lb. horse trailer through the Rockies when it’s 110F in August.  Mercedes tells everyone to use the same oil and change it every 20,000 miles, or whenever your dashboard computer tells you it’s time to change the oil.  You wouldn’t believe how many bulletins Mercedes has published about defective maintenance computers.

Actually the factory has published many service bulletins about the proper oil change intervals. But the Mercedes Marketing Department and Mercedes dealers continue to tell owners they can go 20,000 miles between oil changes. It says it right on the front of the 2019 Sprinter Sales Brochure.  Hidden away in the back of the Owners Manual Mercedes-Benz says this: “The low temperature characteristics of engine oils can noticeably deteriorate during operation, e.g. from aging, soot and fuel accretion. For this reason, regular oil changes using an approved engine oil from the suitable SAE classification are urgently recommended.”  Would it be asking to much for Mercedes to explain what a “suitable SAE classification” means?  How about “regular oil changes”?  Every 100,000 miles would be regular.  The Owners Manual certainly makes it sound like Mercedes is suggesting more frequent oil changes.  It takes the average owner 2 years to drive 20,000 miles. Mercedes maintenance sheets clearly say 20,000 mile oil changes.  In another spot the Owners Manual says: “Using an engine oil that does not have adequate temperature characteristics can lead to engine damage. The temperature range information of the SAE classification always refers to that of fresh oil. The temperature characteristics of the engine oil may deteriorate significantly due to aging in use, especially at low outside temperatures. We recommend that you change the engine oil before the cold season commences. Use an approved engine oil of the specified SAE class.”  Mercedes clearly says the wrong oil can ruin you engine.  Why is it so hard for them to clearly tell owners what’s the correct oil?  Dealers are afraid to say anything different, so they tell owners to use the same Mobil One 5W/30 ESP that comes in the engine.  5W/30 is a cold weather oil that is inappropriate for an engine operating in high ambient temperatures with notoriously high fuel accretion.

Diesel fuel dilutes the oil and makes it thinner.    That’s the fuel accretion Mercedes talks about in your Owners Manual.  If you start with low viscosity 5W/30 oil it becomes very thin when mixed with diesel fuel.  Then the Turbocharger heats the oil to 1600F during the regeneration.  Fuel accretion is nothing new.  The traditional method for dealing with fuel accretion and high oil temperatures is with higher viscosity oil. High viscosity 20W/50 or 10W/60 oil is a much better choice for the extreme conditions in a BlueTec diesel. Mercedes has actually put this recommendation in their 2018 and 2019 Owner’s Booklet. However, they explain it in such a convoluted legalistic manner that it’s hard for the average owner to understand what Mercedes is saying. Mercedes says different oil viscosity is “urgently recommended” and “severe engine damage can result”.   But they never quite tell owners exactly what oil they should use.   You’re supposed to do your own research and figure out all of these technical terms.  These new recommendations also apply to all the older OM642 and OM651 BlueTec diesels.  Mercedes expects the owners of older models to search out the newest oil recommendations and get on board.  The owners manual also reminds owners that engine damage caused by the wrong oil is not covered by the warranty.  So what is the best oil?  It depends on where you live and how you drive.  Is it a new engine or old?  Does the engine burn oil?  Mercedes doesn’t believe in oil additives but I’ve seen them work quite well.  Change the oil every 5,000 miles.  Oil related repairs are ridiculously expensive.

From time to time I’ve mentioned oil Catch Tanks.  Most owners don’t understand them.   What people don’t understand scares them.  If people actually saw what’s involved in a Catch Tank they would see they are very simple and effective.  Mercedes-Benz actually installs a vastly superior version of this on the Diesel engines they install in the European Sprinters.  Mercedes has totally solved this problem but they won’t use it on the OM642.  On this side of the Atlantic we are forced to solve the crankcase ventilation and blow-by problem with a Catch Tank.  A proper Catch Tank cannot harm the engine.  Unfortunately no one makes a Catch Tank specifically for a BlueTec diesel.  You have to modify one that was made for a different vehicle.  You also can’t just put any old Catch Tank on the engine.  This makes a Catch Tank something that most owners won’t mess with.  A Catch Tank captures crankcase oil vapor.  The same oil vapor that causes all of the oil sludge in the EGR, Intercooler and Swirl Flaps.  Better oil and more frequent oil changes will also reduce the oil vapor.  However, if you completely stop the oil vapor from entering the Turbo, there is absolutely no question your engine will pollute less and run better. Seriously, the emission system will function as it was designed for the entire life of the vehicle. You will never need to clean the EGR valve, Intercooler or the Swirl Flaps.  No more sludge in the air intake system.  No more oil vapor “poisoning” the DPF.  The DPF won’t need to regenerate as often, and that means less fuel dilution.  I’ve had one owner monitor the oil vapor captured by his new Catch Tank.  He said he drained off one Dixie cup of oil after 1700 miles of highway driving.  His OM642 has 60,000 miles and has the 8.5 quart oil pan.  He has a new Oil Separator and the best diesel oil. Catch Tanks are for owners with some mechanically aptitude.  You’ll have to open the hood once in a while and drain off the waste oil in the Catch Tank.  There are hundreds of different Catch Tanks on the market.  There is one particular company that makes a really nice one with mounting brackets and hoses that match what’s currently on the engine.  Yes, it cost more than the $29 Catch Tanks on eBay.  No, I haven’t found a cheaper alternative.  Ask your dealer how much they charge for a EGR valve or to remove the Swirl Flaps for cleaning?  Ask them how much it cost to replace the clogged DPF and its pressure sensors?  Ask them how much it cost to replace the clogged EGR pipes?  Ask them how much it cost to clean a clogged EGR cooler?  How much to clean the Intercooler?  Ask them how much it cost for a blown Turbo?  A Catch Tank pays for itself 50 times over.

The factory recommended 5W/30 oil also lacks enough zinc (ZDDP) to protect the timing chain.   The timing chain stretches and you will hear a metallic clatter on a cold start.  Now you get to replace a $3,000 timing chain.  If the oil had approximately 1500ppm of zinc (ZDDP) the chain would have lasted the life of the engine.  This is not unique to Mercedes and Diesel engines.  The EPA oil has been ruining timing chains for 25 years.  The EPA claims they are drawing up new oil specs that will require more ZDDP in the oil.  But it hasn’t happened yet.  Some oils do have the proper ZDDP.  Mercedes actually admits to the timing chain failures in Service Bulletin LI05.10-P-049909. And “NO” they won’t pay for the timing chain.  Soot in the engine oil also causes the Timing Chain to stretch.  Changing the oil and filter more often will help reduce the soot in the oil.

Once your warranty expires the oil vapor finally becomes visible.  Remove the top cover and you’ll see what appears to be oil leaking from everywhere.   Wait a little longer and the “new and improved” oil cooler seals will start leaking oil.   Then the Heat Exchanger warps and leaks oil. The oil soaked rubber seals in the air intake get so hot they begin to leak air.  The plastic Turbo Resonator has been updated five times because it cracks from the extreme heat.  Suddenly the engine goes into “Limp Home” because of low boost pressure.  Get used to seeing fault code P0299-00.  The NOx sensors have also been updated at least five times.  Now Mercedes says the control module for the NOx sensors also needs to be replaced.  If you don’t clean the oil soaked EGR cooler the new NOx sensors will overheat and fail again.  Oil sludge packs the Swirl Flaps and causes the plastic linkage to fail.   All of these problems are solved with better preventive maintenance.  If you think preventive maintenance is expensive, wait until you get the repair bills for cleaning up this mess.

As you drive crankcase Blow-by slowly coats the internal intake and exhaust passages with oil sludge.  Finally the internal passages get so dirty the Check Engine light comes on.  It cost a small fortune to disassemble the engine for cleaning.  Fuel and oil additives help a little, but the mess is substantial.  Finally there is some good news.  There has been a system for cleaning domestic diesels but nobody made the adapters for cleaning the OM642 and the OM651 diesels. There are now adapters for cleaning the EGR and Swirl Flaps without taking the engine apart. This cuts repair cost dramatically.  The same system can also be used to clean the DPF without removal. The system is so cheap that you can own the whole thing for about $700.

After 5 or 6 years owners will often smell exhaust fumes in the cabin.  Owners are often told there is nothing wrong.  Obviously exhaust fumes in the cabin is a serious problem.  It is a legitimate complaint, because the exhaust is known to crack at various places.  If you’ve been told there is nothing wrong, contact me and I’ll send you pictures of the common places the exhaust can crack.  You don’t need to pay anything, this is to important.

Rust in the fuel system causes injectors to clog and drip fuel which in turn  causes the glow plugs to fail.  When a glow plug fails the DPF regeneration stops.  When the regeneration stops the DPF clogs and the check engine light comes on.  It’s $17,000 to replace the fuel system because of the rust.  Then the glow plugs will need to be replaced.  The glow plugs are fragile and can break off in the cylinder head while being removed.  Then you get to pull the cylinder head and send it to a Machine Shop for repair.  Rust in the fuel system is easily preventable.  Rust and tiny slivers of metal can work their way through the fuel system and ruin expensive components.  Attach super magnets to the outside of the fuel filter and on the bottom of the fuel tank.  Zip tie washer shaped super magnets to fuel and oil lines so they can trap any metal fragments.  The magnets are cheap and you can order them off eBay.  Something as simple as a $10 handful of magnets can save you tens of thousands of dollars.

Mercedes-Benz is constantly updating the software for their computers.   The updates solve all sorts of intermittent problems.   Most of the updates are related to the fuel accretion and DPF regeneration.   The updates also correct Fault Code errors.   The mechanic gets a Fault Code but the Code is not for the actual fault.   This is very frustrating for the mechanic that is trying hard to solve your problem.   Mercedes dealers don’t like doing the updates so they tell owners they aren’t needed or have already been performed.  As it turns out dealers have a good reason to avoid the software updates.  Mercedes has slowly admitted that the computers themselves are defective on practically all of the BlueTec’s prior to model year 2015.  It is a very confusing mess and it’s hard to get specific information.  However, this would explain why dealers are so reluctant to preform software updates.  Why do the software updates when they know the module itself is the problem.  If a dealer were to admit this to their customer, it’s just going to be a fight at the Cashiers Counter.  This is currently a huge problem for Mercedes in Europe.  Owners have wasted so much money on expensive repairs that were destine to fail again, and again, because software and control module problems.  Mercedes has admitted that all 2009 to 2014 DEF / AdBlue systems will fail.    It’s a known problem with the level sensors and the heating elements.    NOx sensors are another of the common failures with numerous updates.  The list goes on and on.  As a general rule of thumb; if your engine has a 8.5 quart oil pan, practically every part in the engine and emission system has been updated.  The engines with 13 quart oil pans have most of the updates.  Most but not all of the updated parts will work on the older engines.  The cost of replacing all of these parts on an older engine can be substantial.

As of 2019 B20 biodiesel will be sold in every state.   You better start paying close attention to the pump.   At one time, Mercedes did a fair job of explaining the damage caused by B20 biodiesel.   However, Mercedes must have gotten a call from the EPA because Mercedes really toned down their admonitions about B20 biodiesel in their latest sales brochure.  Just so we’re clear on this, Mercedes does not approve any biodiesel above B5.  There are large parts of America where you can only buy B20 biodiesel.  Mercedes will not warranty the damage caused by anything above B5 biodiesel.  So what do you do, when you have no choice?  There are additives you can put in the oil & fuel which will mitigate the damage.  But Mercedes says you can’t use additives in the oil or fuel.  Now what?

I’ve shortened this article because it was getting long and technical.  It’s still to long and technical.  I’ve left a lot out.  Every problem has a solution and a way to prevent the problem.  I get a lot of calls and emails from owners who want more information about how to take care of their BlueTec.   Most Sprinter owners have invested a lot of money in their vehicles.  When SUV owners have problems with theirs they abandon the car.  They just can’t justify the repair cost. Sprinter owners can’t walk away from their investment.

If you’re buying a new Sprinter, you have a once in a lifetime opportunity to properly break in the engine’s piston rings.    The engines come with standard Mobil One ESP synthetic motor oil. Because of fuel dilution BlueTec diesels need to have a perfect seal at their piston rings.  The EPA wanted to reduce the waste oil going into the environment.  So the EPA made everyone stop using the break-in oil for the first 1,000 miles.  If the piston rings have a perfect seal against the cylinder walls, you’ve got a way better chance of keeping fuel accretion to a minimum.   It’s much harder for fuel to get past well sealed piston rings and into the crankcase oil.  You only get one chance on a new engine to get this right.   Plus, it’s simple to do.   But don’t bother asking a dealer to do it.   You’ll just get the big horselaugh.  “Who told you to do that?”   “That’s old school.  Nobody does that any more.”  If it’s old school, why does Bugatti, Ferrari, Lamborghini, McLaren, Koenigsegg and even Pagani with an AMG engine; all continue to use Break-in oil in their new engines?  If there was ever an engine that needed Break-in oil, it’s a BlueTec diesel.

Mercedes-Benz no longer offers factory rebuilt engines for the early versions of the OM648, OM642 and OM651 BlueTec Diesel.  The EPA wants these old engines off the road.  The emissions are way to dirty.   There are currently a number of class action lawsuits over the BlueTec Diesel.   The emission systems are stressed to the limit of technology.  Owners hold out some false hope that these lawsuits will somehow help them.  I hear from so many distressed owners who have been denied warranty on their ruined engine.  They want to know if there is some way to force Mercedes to honor their warranty.  Honestly, there isn’t much hope.  There is only one source for a decent third party rebuilt engine.  Even then, there is more to it than just replacing the engine.  I hear from owners who are so financially upside down that they can’t walk away from their car.  If you’re really stuck, there is only one way to untangle the mess.  It will still cost about $5000 to $7000, but the repair will last.

I’ve never understood why people would rather fight with Mercedes than change their maintenance routine.  Some people think I’m just trying to drum up business for my shop.  I’ve retired.  It doesn’t matter to me if you service your vehicle at the dealer or do it yourself.  However, I would like to fund my 3 year old Grandson’s college savings plan.  I have a small window of opportunity to use my experience to help owners and my Grandson.  I’ll explain the preventive maintenance in a way that you will understand.  Once people understand what’s going on they find life with their BlueTec diesel much easier.

If you want additional help, you can email or call me.  It’s $200 and goes to my Grandson’s 529 college savings plan.  I’ll send you a link to PayPal.  I’ll send you detailed instructions about the problems and how to avoid them.  I’ll explain the things dealers can’t tell you about.  By the way, this is not a rant about Mercedes dealers.  They are in a Catch 22.  It is not easy keeping the government, Mercedes and their customers happy.  I also don’t sell anything.  I don’t have a vested interest in where or how you spend your money.   This article is only a small part of the issues surrounding a BlueTec diesel.   I couldn’t possibly put everything here.   When I send owners the rest of the stuff on this engine they always are stunned by all information.   I’ve even had a lot of dealer Mechanics, Service Advisors and Sales people who have ask for help.   They work for Mercedes and have never seen all of the stuff on this engine.  I’ve had a few Sprinter shops ask me to come help them sort out the problems they see in their shops.  On one hand I would like to help.  On the other hand I’m 70 and life is short.  If I could combine several shops into one trip, I might consider it.  I’m defiantly not going where it’s cold.

It doesn’t matter if you have a new Sprinter under warranty or an older model that’s burning a quart of oil every 200 miles.  Nothing I tell you will affect the warranty. I’ve heard of dealers telling owners not to change their oil before 20,000 miles or it will void the warranty.  Tell them to put that in writing on your Repair Order.  There is no way Mercedes can void your warranty because you change your oil every 5,000 miles.  My goal is for you to never need the warranty. Zero warranty claims is a victory.  Success is 200,000 miles on the engine and the emission system still works like new.

Mercedes-Benz has greatly improved the new OM642 BlueTec that comes in a new Sprinter.  The engine is waaaay better than the older versions.  If you’re thinking of a new Sprinter, I can explain the best options that are really helpful.  For example; Sprinter offers an auxiliary battery.  You should order the auxiliary battery because it gives the electrical system the extra voltage it often needs at peak load.  When mechanics scan your diagnostic computers they often find low voltage fault codes.  Even though there is often nothing wrong the low voltage code is still telling you the system voltage is intermittently to low.  It’s better not to have low voltage fault codes.  So just order your Sprinter with the extra battery. That’s actually why Mercedes offers it.  I’ll also tell you what options are a waste of money.  For example, never buy the Prepaid maintenance plan. They’re charging you $600 for an oil change once a year.  The Owners Manual says the engine needs two oil changes.  Mercedes advertises this as “locking in your maintenance cost so there are no surprises”.  The surprise comes when you find out that everything except the oil change cost extra.  I used to think the extended warranty was a smart idea.  But I hear from to many owners who can’t get Mercedes to pay the claims.  I would still recommend all the extended warranty you can buy.  It is transferable to another owner and adds value.  Just be aware that you can’t ignore the maintenance and think Mercedes will pay for your negligence.  When the engine locks up at 75,000 miles, Mercedes will read you the fine print in the back of your Owners Manual.  What it says in the Sales Brochure and what it says in the back of the Owners Manual are not the same.  My goal is for you to never have that discussion.
You can reach me at, or 916.715.0665.