The Chief

Hi all,
I am new to the forum and the MB world. I have bought a 2006 E320 CDI and my only regret is that I did'nt do this years ago......
A friend of mine drives chevy diesel (duramax) and he keeps telling me to use fuel additives to give extra lubrication to the pump and to further increase fuel milage. Does any of you have any experience - good/bad - with fuel additives for diesel engines. Any advice will be greatly appreciated. Thanks.

harkgar

Hi Chief,

My wife and I have been driving Suburbans since 1991 and the three quarter ton is our 4th or 5th. Fairly reliable though like all cars luck plays a big part.

My E320 CDi is 2007 but very similar to your 2006. It is the best of recent MB diesels because it can burn both LSD and ULSD. The 2007 and newer ones can burn only LSD. It also has one catalytic converter (less to go wrong and to replace). Without all the latest tree-hugging rubbish you can use most of the combined diesel catalyst and fuel additives. It is a moot point really as most auto stores do not sell anything but ULSD compliant additives.

No matter what I put into my tank I cannot blow black smoke. Pity.

harkgar

Chief: my diesel is the same model year as yours, 2006.

harkgar

Chief:

Redline diesel catalyst is good. However, I find that using nothing but the best diesel is more cost effective. I am referring to Sunoco Gold Diesel and Shell Gold Diesel. A bottle of additive will set you back $7.00 or so plus taxes in Toronto which means higher costs then pumping the higher cetane fuels.

In the snow belt states winter diesels also contains anti-gelling additives which may be absent in some after market additives.

Go for the best diesel fuels. Avoid all veggie stuff. Your engine will thank you for it. Tell the tree huggers to forget it. Fossil fuel is best.

TMAllison

Additives aren't needed in your engine, anymore so than they are in mine. If it makes you feel better, put a splash in each tank.

ULSD meets all ASTM requirements for lubrication, no different than LSD did before it, or than "super duper extra ultra low sulfur diesel" will in the future.

Use 5% bio; no more per MB.

240D 3.0T

The E320CDI (and your friend's Duralax) were designed to use ULSD from the start, "extra lubrication" is a complete waste of money.

The Chief

Hi, thank you all for the reply's.
I guess my biggest reason for maybe trying the additives would be the extra fuel milage. The car is already "out of this world" when it comes to fuel milage - I bought it in Atlanta and drove it out to wilmington NC and running 80-90 most of the way I averaged 38 mpg. Coming from a 97 suburban with 33's, lift kit and a 12 mpg average I laugh everytime i drive the benz :-)
But..... I keep wondering if I somehow could hit the "magic" 40 mpg on the high way.
Ahhhh, what I got already beats almost everything on the road so I guess I should just "settle" for what I got. Again thanks for the reply's.

harkgar, I have the same problem.... cant show the tree huggers any black smoke ;-)

TMAllison

40mpg should be easy at 65mph, IF you can get 38 at 80-90mph......Skeptical though......Maybe it was all down hill?

The Chief

Hi TMAllison, my thoughts too but no not easy at all. The trip back from Atlanta was a 475 mile none stop trip, almost all of it on interstate - and no it is not all down hill. With normal mixed driving around home - city/highway - i average 32mpg on a tank.
I can dublicate the 38mpg on long trips but 40mpg dont seem possible.

240D 3.0T

A good tuner, not the plug in box cr@p, will increase both maximum power and fuel economy.

lkchris

This is basically fantasy.

What mechanical change would a "liquid solution" provide that could somehow make a given drive less work for the engine?

Your fuel system does not need "more lubricity" and if someone could magically (and that's what it would be) provide it it wouldn't make any difference. Given "contamination" of your fuel with an additive, how do you know that that additive contains equal BTU of inherent power than just plain diesel fuel? It's not likely and it's more likely you'll be burning a fuel mixture containing less power, which means it takes more of it to do the same amount of work.

In 2010 you'll be able to purchase a 4-cyl diesel C-class and this smaller engine ( about 2.2 l) moving a smaller, lighter car will definitely provide better fuel economy. That's the sort of thing that's required, not, again, "liquid solutions.."

harkgar

I agree with you.

I sincerely hope you are right with the C220 CDi. I have only read about the E220 CDi (Blue Efficiency?). This engine produces similar output to the old inline 6 and if regulations do not get worse urea injection may not be required. Perhaps a 6 speed manual?

240D 3.0T

Funny, the editors of this months Mercedes Enthusiast were complaining about it having a manual.

The Chief

Hi lkchris,
Thank you for your reply. I laugh at all these "wonderful products" that if you just buy a little of this your car will "run forever on nothing".

With 6 1/2 years of advanced technical education (certified master machinist, degree in mechanical engineering, degree in electrical engineering) and 17 years of experience in the technical world I believe in technical facts and not technical promise.

When looking at the fuel efficiency of a diesel engine there is the "mechanical aspect" like spray pattern, pressure, temperature, air mixture ect. but there is also the "chemistry" part of it which would be fuel quality, cetane rating, burn rate ect.

To me the MB engine is one of the most efficient ever build but if you test the exhaust there WILL be traces of fuel. The better we can burn the fuel in the cylinder and hereby reduce the traces of fuel in the exhaust the better the efficiency and the mpg.

"harkgar" has mentioned that to him the most cost effective is to buy only the highest quality fuel. That will give you a more complete combustion/fuel burn and therefore also a better mpg.

If an diesel fuel additive should work it would be because of an increase in cetane rating and perhaps other improvements. If the "chemistry guys" can come up with an additive that can get us closer to a complete burn in the cylinder and hereby zero traces of fuel in the exhaust then you will get a better mpg. It of cause has its limits, which in theory will be when you reach the perfect combustion where all the fuel burns up completely in the cylinder.

"Independent" tests of Stanadyne's (the only company making both additives and fuel pumps/injectors) fuel additive shows a better burn and hereby a better mpg. Do I believe that..... No I only believe in my own tests.

Long long story short, I have zero experience with these additives and therefore asked the fine people of this forum if anyone here had some experience in the world of additives.

Again thank you all for the reply's.

lkchris

Doubt it.

Every drivetrain means an expensive EPA certification. Ain't gonna happen for likely low volume models.

240D 3.0T

The Chief, if such a simple chemical solution existed to so drastically reduce fuel consumption and emissions then every diesel engine manufacturer would be screaming for it to become part of the diesel fuel standard. A $3,000 particulate filter and de-NOx cat system wouldn't be needed. (The system costs $8,000 on semi-trucks!)

mtnroads

it would seem that unless the additive was more combustable than diesel (more available heat/power) it would just displace fuel that would normally be used to propel the car. to keep the math simple if you added 10% additive, only 90% of the remaining fuel would be left to move the car. on 2 stroke engines (snomobile) adding more lubricant displaces fuel and causes a lean condition (needs larger jets). it is a common misconception that adding extra oil to 2 stroke mix will be safer for a hot engine. lean mixture accelerates engine failure.