Sprinter engine issue using bio-diesel

[HAF]

My sprinter was a 2014 Sprinter 2500 with the 4-cylinder engine. Awesome van. Awesome engine. I had purchased it new and took great care of it. At around 14,000 miles, the engine oil warning came on. Fortunately I was within a few miles of a local Mercedes dealer which allowed me to roll in and get it checked. I was surprised to discover that the engine oil level was HIGH. The dealer cleared the code, drained a little oil (I had not added any) and I was off. A few weeks later, it happened again. With this I decided to do a little searching to discover what was happening with my engine.
Long story short-Mercedes has a web page dedicated to the use and warranty issues with engines using bio diesel. They warrant engines that use %5 or less blended bio diesel. Anything more and your out of luck. It seams the combustion chamber on Bluetech engines does not completely burn bio diesel which results in the un-burned fuel being squeezed into oil pan. This causes the oil level in engine to rise. Fuel in oil is not so good for your engine or emissions system. The Mercedes page addressing this goes as far as advising customers who own these vans/engines to park in a cool place if the van is parked for extended periods. There are other tips as well that read like orignal owners of model T's! Due to the fact this van would be mostly used in the state, I had to get rid of it for a significant loss (paid over 45k, got 28k for a 15k mile perfect shape Sprinter).
The state of Minnesota passed a law requiring all diesel fuel to be blended with at least %5 bio fuel. There is-was a plan to increase this percentage to 20 by May of 2018. I reached out to a few dealers of Sprinters (Mpls) and asked them about this situation. The responses where weak and vacant. For those who buy these vans for work-like a plumber or electrician who cant get out of the state to re-fuel with no bio fuel, they are stuck. Stuck with a non warranty engine failure. Its not right.
I currently have a Sprinter camper with V6. I never refuel in MN and always make sure to top of in states where they dont have bio fuel.
My daughter has a Bluetech SUV and experienced issues when she lived in Chicago. She traded that vehicle for a Mercedes gas SUV. Illinois also has bio diesel at the pump.
So-make certain that you read all the stickers on the pump you are about to use for refilling your Sprinter and try to avoid blended diesel.

 

[luthj]

The cause of oil dilution is a bit more complex. In order to regen the DPF the exhaust temps need to be increased for a period. This is done by injecting some extra fuel into the exhaust stroke, which then burns. At low temps, and light duty driving, some of this fuel can condense on the cylinder walls, and get washed into the oil. With normal diesel, this amount is minuscule. However, some types of biodiesel have a higher flash point (less volatile), so significant amounts can end up in the oil under certain circumstances. This is compounded by low temps, and low load driving during regen. I would guess you drive quite conservatively in a lightly loaded van, and you may have lots of stop and go traffic/low speed driving.

All the above applies to high biodiesel content. 5% bio doesn't generally have these effects. Are you certain your oil was high due to dilution? Its not unusual for dealers or lube shops to overfill the oil (its a hot check dipstick). When the engine oil gets really warm, and you drive on steep hills or high RPM, it can trigger the high oil alert intermittently. Oil analysis is generally about 70$, and will definitively identify dilution.

While oil dilution is a concern, reducing the oil change interval can effectively mitigate the problem. As can using a scangauge or other device that can be configured to alert you when a regen occurs. Generally speaking getting on the highway for 30 minutes every 400 miles or so may be required for a regen in some regions. Just the nature of the post 09 diesel beast.

 

[HAF]

Thanks for your reply. I used the van on several cross country trips reasonably loaded. Prior to running into the issue, several trips had been made in Mn and Iowa with same equipment load. We kept it in our heat building and never idled it. A few Mn lawmakers are aware of the issues with Mn fuel and Mercedes warranty. I was told the the state lawmakers where planning on bring a bill forward requoring dealers to disclose all information to customers.

 

[Weeds]

I have a Grand Cherokee Ecodiesel. The manual says to change the oil twice as often when using the 20% diesel. I used some when not paying attention and it clogged one of the exhaust sensors.

 

[HAF]

The Mercedes manual on this advises parking in cool shaded areas and not storing with this fuel for extended periods. I absolutely prefer diesel engines-just not this new fuel that goes in them.

 

[BADDANDY]

My 07's manual said don't use Bio-diesel period.