Gas Mileage for a Mercedes 3.5 Diesel

[Jack1234]

Very interesting discussion concerning the possible impact of bio-diesel blends. At the end of the day if some of the current Diesel engines (specifically the Mercedes blu-tech) are really not capable of adapting to blends over 5%, then it would seem inevitable that Mercedes (etc) will simple discontinue sales of the engine in N.America, rather than deal with endless warranty disputes and knowingly sell an engine that is unsuitable for the marketplace. This does not suggest a very encouraging future for this platform.

[smiller]

It's not just the Sprinter platform, it's all Mercedes diesel engines (and BMW, and Volkswagon, and Audi, and many others, all of which say no more than %5 BD.) It seems unlikely that all these manufacturers would discontinue all sales of all diesel models in such a lucrative market. More likely they will adapt. Kicking and screaming maybe, but they have little choice.

Makes me wonder though... the mechanics involved are similar no matter who builds the engine... are all the European manufacturers too worried or are the US manufacturers not worried enough? Time will tell I guess.

[Showkey]

Toyota, Honda and Mazda all had plans and announced diesel trucks or cars. All have put those plans and products on hold. Two of the three specifically sighted inconsistent diesel fuel quality in the US market that made it difficult and expensive to meet long term durability emissions tests. All have diesels in other markets. Honda was going to offer an engine that passed diesel emissions without using DEF ( blu-tec). Mazda was the most recent to pull back on their diesel plans.

Fuel quality is not just bio blend, that one does seems not be big problem yet. Soot, wide varying cetane levels ( big problem) sulfur and other contaminants and just poor quality fuel is the problem all these make for dirty diesel emissions that must be dealt with.

Ford and Chrysler both seem to increasing their diesel offering in the US market. I do not think MB slow or stop their diesel offering any time soon. If they do pull out of the market it will because the competition kicked their butts by offering better cheaper products. That remains to be seen and might two years to prove out. They are not likely to retreat and will hit the market with new product but true to MB it will NOT be cheap.)

This fuel thing run deeper than diesel............EPA wanted to jam 15% ethanol down our filler necks.......that seems to be on hold for now.

[wanderso]

Hmm... Tells me to not bother to buy one of these as a used rig. Of course some would say the same with mine and the V10 spark plug blowout issue, so I guess we're even.

[IamJerryP]

OK, I have to know, just how Mercedes knows what fuel you are using, or used 10,000, 20,000, or more miles ago.....
in my younger days I worked at several car dealerships, know a bunch of people who still do, plus, RV, and Boat dealership people, and never once have I heard of the dealer being concerned about what fuel was being used, nor have I ever heard of a warranty repair being denied over fuel......

[Showkey]

They do not know what fuel you used yesterday. .

Wonderso ......
As for not buying a diesel (new or used) there are many more considerations and reasons but blended fuel is not even in the top twenty. It would be like saying I will not buy a v10 gas engine because many states mandate only ethanol blend and I get worse mileage, water in the gas can be a problem, corrosion and no start in spring from stale fuel from sitting ( can be a problem in an RV). These are all problems with gasoline...........we deal with them. My lawn mower and motorcycle get stored with Stabil to avoid the problem. There are things to worry about.......

[elektron]

Originally Posted by Showkey

...
Also Sprinter chassis and cruise control is not the way to get good MPG. Want better MPG do not the cruise.........slow a little on the up hill, speed up on the down side.

I seldom drive my Navion IQ without having cruise control engaged. The last two tanks of fuel have averaged 17.4. This includes sustained driving at 60 to 70 mph and running air conditioning. Cruise control, in general, will return at least 7% better fuel economy used correctly. The key to getting the best economy is to restrict acceleration. Fortunately the Sprinter does not require a lot of throttle to accelerate at an adequate rate.

Cruise control is at it's most effective when going slightly uphill. It will use less throttle than a human to maintain speed. Coasting, using little throttle to accelerate, and minimizing waiting at lights (by timing your arrival) are all useful to improve economy. I have a VW Passat rated at 34 mpg (highway) that I get 48 mpg out of doing this.

The Sprinter gets twice the fuel economy of my class C Ford chassis v-10 under the same conditions. To be fair the Ford chassis was larger and heavier and the handling was horrible.

The were a few Sprinters with 3.5 gas motors but not common in the US market. Did not think they were sold to Class C RV manufactures. If they were that would be something to avoid.

The 2008 View had an option for a 3.5L 254 hp Gasoline V6. The V6 3.0 L Diesel produced 154 hp then and 188hp now. The owners of many of these had Dodge emblems on the hood, most of which have been replaced to Mercedes Benz emblems to reflect the engine maker. After Mercedes-Benz split from Chrysler the chassis cabs used by RV makers have typically had the big Mercedes Benz Tristar emblem on them.

[elektron]

Originally Posted by Jack1234

Very interesting discussion concerning the possible impact of bio-diesel blends. At the end of the day if some of the current Diesel engines (specifically the Mercedes blu-tech) are really not capable of adapting to blends over 5%, then it would seem inevitable that Mercedes (etc) will simple discontinue sales of the engine in N.America, rather than deal with endless warranty disputes and knowingly sell an engine that is unsuitable for the marketplace. This does not suggest a very encouraging future for this platform.

In this country the biodiesel producers, last I heard, still do not have the capacity to make up even B5 which is what is desired. Daimler is not the only maker who will not certify their modern engines for a higher concentration than B5. Most makers do not. Older engines in some cases run fine even on B100. The problem is that Biodiesel will dissolve some of the seal materials in an engine.

The largest seller of Diesel automobiles in the USA is Volkswagen, who has the same restriction on their engines. Fortunately most Diesel engine owners are aware of the restriction and avoid mixes with more than 5%.

I do not see the Germans ceasing to sell Diesels in NA. I see everyone who sells vehicles beginning to sell Diesels if they are not already. The CAFE standards are a part of this. The Japanese are coming late to this party, but think they have some good designs.

If not for the higher price of the engine, A Diesel of comparable road performance to a Gasoline engined vehicle will return better fuel economy and much longer life.

If Biodiesel supplies improve, I see the engine makers adopting their engines to use higher concentrations.

Biodiesel is often used to add back the lubricity lost with the reduction in sulfur in road fuel. It will also purge the fuel system of tank clinging debris resulting in a clogged fuel filter if suddenly used in a system that had not ever had Biodiesel fuel in it before. The same thing happened to some people who switched to ULSD from Premium Diesel No. 2.

[elektron]

Originally Posted by IamJerryP

OK, I have to know, just how Mercedes knows what fuel you are using, or used 10,000, 20,000, or more miles ago.....
in my younger days I worked at several car dealerships, know a bunch of people who still do, plus, RV, and Boat dealership people, and never once have I heard of the dealer being concerned about what fuel was being used, nor have I ever heard of a warranty repair being denied over fuel......

There are actually several ways the dealer or maker can tell what you used. Oil analysis, fuel analysis, and examination of fuel lines, filter, and tank can all give evidence as to what fuel was used. I expect looking at the injectors (spark plugs too)will also give clues.

The easiest way to tell if someone used too much Biodiesel, will be from the damage it causes. This is NOT just a Diesel engine issue. Run nitro in your gas engine and you have no warranty.

Alter your computer, and you have no warranty and the possibility of a $Ks fine and time in prison if you increase pollution. Most people who want to make alterations wait until the warranty has expired and are willing to pay for the repairs they might cause.

Are you familiar with reading spark plugs to determine engine faults?

We are talking about Fuel at the moment. The restrictions on the OIL you use are just as, if not more, important. Oil is tailored to the engine now as never before. You can't just buy 0/30 these days and expect that will be the only criterion. Now you need to know the EXACT spec that the engine maker REQUIRES.

[elektron]

Originally Posted by Showkey

They do not know what fuel you used yesterday. .

Wonderso ......
As for not buying a diesel (new or used) there are many more considerations and reasons but blended fuel is not even in the top twenty. It would be like saying I will not buy a v10 gas engine because many states mandate only ethanol blend and I get worse mileage, water in the gas can be a problem, corrosion and no start in spring from stale fuel from sitting ( can be a problem in an RV). These are all problems with gasoline...........we deal with them. My lawn mower and motorcycle get stored with Stabil to avoid the problem. There are things to worry about.......

Long term storage with Diesel fuel should also be accomplished with a fuel stabilizer. Diesel fuel grows ALGAE in it, which is what tends to clog the fuel filters and sticks to the sides of the tank (now usually plastic to reduce this issue).

Of course problems with Gasoline engines are just as plentiful. If not for the modern computerized injection systems holing pistons and being required to use Premium fuel would be a major issue for almost all engines. The engine management system DOES alter it's operation based on the fuel being used. I would BET that remains in it's memory too.

[IamJerryP]

Originally Posted by elektron

There are actually several ways the dealer or maker can tell what you used. Oil analysis, fuel analysis, and examination of fuel lines, filter, and tank can all give evidence as to what fuel was used. I expect looking at the injectors (spark plugs too)will also give clues.

The easiest way to tell if someone used too much Biodiesel, will be from the damage it causes. This is NOT just a Diesel engine issue. Run nitro in your gas engine and you have no warranty.

Alter your computer, and you have no warranty and the possibility of a $Ks fine and time in prison if you increase pollution. Most people who want to make alterations wait until the warranty has expired and are willing to pay for the repairs they might cause.

Are you familiar with reading spark plugs to determine engine faults?

We are talking about Fuel at the moment. The restrictions on the OIL you use are just as, if not more, important. Oil is tailored to the engine now as never before. You can't just buy 0/30 these days and expect that will be the only criterion. Now you need to know the EXACT spec that the engine maker REQUIRES.

You worry way too much..........

[HHg]

Our first RV was a Coachman Prism 240 on the Sprinter chassis with the Mercedes engine.....that little thing always got between 12-15 mpg depending on terrain. The Sprinter chassis handled SO good and was SO easy to drive.

Hhg

[Murf2u]

Originally Posted by IamJerryP

You worry way too much..........

My nieghbour didn't worry enough. The great mileage his new diesel VW SUV got still wasn't good enough for him, so he made a deal with some guy he works with and who makes his own 'home brew' bio-diesel.

Within a year it was at the dealer in pieces when they told him he'd violated his warranty by using unapproved fuel in it.

The bill was the best part of $10k.

[Showkey]

Home brewed fuel is a whole different issue vs commercially available bio blend 5-20 % that is some states you have no choice. When the fuel smells like French fries that a clue it could be a problem. There are obvious risks with home made fuel that is one step above mixing drain oil back into the fuel tank and thinning back with gasoline. ( NOT a good idea). . To save money ;(

Over at the Sprinter forum nobody is concerned or even mentioning any problems with the high pressure pump, injectors or other key components in fuel system.

Main issues are

1 EGR system sooting MB does not have the market cornered on that problem everybody has that problem even gas engines.

2 Low power due to air charge leaks cause by a sensor, hose, clamps, gaskets etc

3. DEF issues. Sensors, and internal tank issues. 2010 and newer

4. DPF Issues Usually high mileage. Most are 150-250 k

5. Swirl valve issue. Again usually high mileage. Some these are 150-400 k

Most of these are emissions warranty covered if they occur under 80-100 k .

Since its the internet there is no way to quantify the numbers of these problems vs people that do not have a concern or do not use the forums. But I do not recall one high pressure pump.