Diesel Fuel Quality - PeachParts Mercedes-Benz Forum

JerryBro · #1 05-21-2003, 06:06 AM

We had been filling up at the local Sunoco until recently. Running a tank or 2 of Getty made a noticable difference in mileage, from 26/27 mpg to 29/30 mpg. Going back to Sunoco saw the mpg drop back down. This weekend we filled at a Mobil nearby. Haven't gone thru the tank yet, but there is a noticable increase in power and we have gone farther on half a tank than ever before.

Have any of you seen anything similar? It's an 84 SD and we use Power Service with every fill up.

Jerry

Antony · #2 05-21-2003, 07:43 AM

Can't say as I have ever noticed a mileage difference between brands.
My '72 only goes thru about 1 tank a year, so it doesn't count.
In my '95 I do notice a difference between regular unleaded and super but that's due to the octane difference.
Take a look at the deisel pumps at the different stations, each one my have a different cetane rating, that would account for the variations. The higher the cetane the better the quality.

Mike123 · #3 05-21-2003, 08:38 AM

I have noticed pretty significant mileage differences between brands, also. Or, perhaps, I should say between stations. My driving mix is about the same on each tankful. I have noticed this difference seems most noticable during changes of season. I attribute this to some stations still having winter mixture and others having switched to summer mixture. I usually buy fuel at one of three different stations and by about June 1 I find that the mileage differences end. This is ,of course, only my opinion.

dave240 · #4 05-21-2003, 08:48 AM

JerryBro,

I have certainly noticed a significant increase in gas milage since the winter, doing the same type of driving.

Amoco has one of the highest cetane ratings around here (no.VA)
they claim cetane of 48. But you pay for it. Texaco is around 45.
Hess also around 48. it think. Many places don't seem to post the rating for some reason.

Elliott Fager · #5 05-21-2003, 09:24 AM

In Washington state, I have been using Cenex fuel for years. Many of the other fuels mentioned in this forum are simply not available here. Cenex fuel makes my 81' 300SD run much quieter and smoother at an idle. It is the best "treibstoff" I have ever used. I generally will try to plan my fill-ups based on when I'll be in the vacinity of a Cenex fuel station---I like it that well. My mechanic suggested that I give it a try. I am addicted to it now! My mileage has increased about 1.5 - 2 mpg. Past fuels used were Chevron, Texaco and BP

P.E.Haiges · #6 05-21-2003, 10:33 AM

Over the past 35 years driving MB Diesels, I have run then on all kinds of fuels: Kerosene, #2 fuel oil, gasoline and oil mix, and pump Diesel fuel. I could never tell a difference in running but I never did a mileage comparison. Being that a Diesel engine is a multi fuel engine, they run on a variety of fuels.

I remember when I had my first MB Diesel a 180D, I could get kerosene for $.15 a gallon. Gasoline was about $.30 a gallon then, circa 1968.

I haven't tried Vegetable oil yet but I would like to start soon.

P E H

Muck · #7 05-22-2003, 01:46 PM

Anyone tried using biodiesel? A friend of mine in New England keeps telling me I should use it.

And, if so, does anyone know if they sell it in Kansas City? The closest I've seen it to KC is in Iowa...but, that's a bit of a drive for some petrol...

franklyspeaking · #8 05-22-2003, 02:42 PM

Well...I guess I'm the odd-ball. I check my milage with every fillup and I see no difference in any of the three different brands that I use regularly (Williams, Amoco, and Independent). I do see some difference from fillup to fillup related to the amount of highway driving vs. city driving and whether I have used my utility trailer, but no differences that point to the fuel brand. Being in the south, I don't think that winter formulas are used here?

As a BP employee, I would like to say that the Amoco Diesel is far superior and my milage is much better while using it, but I would not be truthful with such a report. The cost is the ony difference I can see.

#9 05-22-2003, 03:41 PM

Antony,

Do you use any fuel conditioner in your '72? I run maybe 3 tanks a year through my '86 SDL and am interested in finding a conditioner that will suspend any H20, provide algaecide, and increase cetane. Any ideas?

bjcsc · #10 05-22-2003, 06:04 PM

I'm with franklyspeaking. Amoco Premium Diesel here runs $1.49/gal, only about $.05 more than Hess/BP etc. I notice a mileage increase and better overall performance with it. I do think it has more to do with the cetane rating (which is 50 at the station I go to and who knows what at the others). They're the best nickels I spend. I've always wondered why they don't have to post the cetane rating like they do the octane ratings. Why don't the diesel drivers get any consumer protection?

rwthomas1 · #11 05-22-2003, 09:15 PM

I have some freeware in my palmpilot that allows me to track mpg. The mileage nevers seems to vary by more than 1 mpg + or - and seems to be more related to type of driving and how heavy my foot was. MB averages 26.39mpg, GM averages 18.53mpg (but that includes some heavy towing). I have noticed that fuel quality is more uniform in NE than it was in TX. Every once in a while in TX I would get a tank that would really rip or one that was cat pee. RT

84300DT · #12 05-23-2003, 05:58 AM

jerrybro- i have also noticed a better performance from getty, as opposed to the citgo that usually goes into the tank (cheapest)

i try to stay away from sunoco..