My 1995 C280 has a capacity of 16.4 gallons, which includes a 2.1 gallon reserve (low fuel light).
Now, I think something fishy is going on with the Local Mobil gas station here in town.
About a week ago, I ran my gas tank down to the very bottom (actually ran out of gassing pulling out of my driveway). I wanted to get the tank as empty as possible; didn't intend to actually run out!
Well, I had my brother go down and fill up a gas can for me. Ok, so I loaded one gallon of gas into my car. I then drove the 1/2+ mile to the nearest gas station (the Mobil). Once there, I filled my tank with 17.4 gallons. Therefor, I filled a 16.4 gallon tank with 18.4 gallons. Is this possible? Do they not include the fuel lines, spout, etc, in that capacity? I did fill the tank for another 1/2 gallon after the pump automatically stopped, but did not top the tank off.
I have had a number of these incidents at this mobil, and didn't know if it was just my car or what? Then a friend of mine said the same thing... she would get "15 gallons" according to the pump, but it would only put her at 3/4 of a tank.
If there is no way in Mercedes Hell that you can fit 18.4 gallons into my 16.4 C-class gas tank, then the Mobil is screwing me, and probably every other car that comes through. Help me, I have tried to contact Mobil, the Corporate Office, I think it's Exxon or something, actually, or maybe even something different. But can't get through. I have saved a number of receipts stating 17 and 18 gallon fill-ups (in 16 gall. tank). What should I do? Find another number and call again?
Thanks everyone.

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

David,
Here in Kentucky we have a government agency called the Department of Weights and Measures. Their job is to check all places that sell products by volume or weight. The pump or store will have a certificate stating when they were last checked.Maybe you should check with your government to see if they have a similar agency. I would bet they have one.
Bill Lewallen; Lexington,Ky.Home of fast horses and pretty women.......or is it the other way..

Fill up a 5 gallon container at the Mobil. If it takes 6 gallons be suspicious.

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JSR

1983 300D Turbo
1995 E320 Wagon
2001 MR2 Spyder
2001 Subura WRX Sedan

I saw a 20/20 program about gas stations that were running a short fill scam in San Diego. The way it worked was the pump dials would run faster than the actual pump until it approched 5, 10 & 15 gallons, then they would run slower until the actual amount caught up. This way if you bought gas in increments of 5 galons it would be correct. But if you bought any where in between it would be off by as much as 15%. Clever way to get by the weights and measures people but still cheat. I believe that this was in the early 90s. In short don't fill one five gallon can but fill five 1 gallon cans to test the system.
Most likely you are filling the tank and the filler neck to the max without leaving any expansion room. The practical fill volume is what is listed in the owners manual. This would be the amount that would leave a small amount of space for expansion and the filler neck would not be included.

__________________
Dave
88 300E 250K Sold
2000 C230K Totaled @104K
2003 ML320 156K Sold
2009 E350 4Matic Sport 46K Sold
2011 ML350 60K Sold
2014 GLK350 46k
2012 GL450 55K

One thing about the C-Class tank! It's plastic & can *stretch* a bit, have seen several that would take 17Gal.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
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44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

The owners manual translation from the German leaves a bit to be desired. I encountered the same thing with my 300SD. The reserve is NOT included in the tank size, it is IN ADDITION TO, so your tank should be a nominal of 16.4 gallons PLUS 2.1 for a total capacity of 18.5 gallons.
You can prove this in two easy ways: 1. Are you getting good gas mileage? If the gas station was seriously screwing you, you would be getting very bad mileage figures, 2. Try filling up at a different station to see what the numbers look like.

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles

Good idea Ron; actually I filled up at a Chevron today (cheaper than the mobil over by where I work). I was able to barely squeeze 16 gallons into it and I was pretty darn low.
Wow, a gas tank that expands!!
In my owner's manuel, it's fairly clear that the 16.4 gallons INCLUDES the reserve of 2.1... maybe it's not?
Maybe I will get around to doing the test, but I'd have to buy 3 5 gallon tanks! Maybe I will just report it to whatever organization does California's gas station monitoring or whatever. I will let you know the figures of my mpg after this gas tank. My last tank I averaged 19.50 mpg, but I drive pretty hard! I should be getting 23 (20 city 26 hwy, accoring to MB), because I do about 1/2 city and 1/2 hwy. So not too bad, but I will let you know of the results at the end of this week when I fill up again.
Thanks everyone.

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

Ok, then if I fill up my tank until the pump automatically stops, is it fair saying that I've have a total of (including what was in their) apprx. 16.4 gallons of gas into the tank? Because I want to get real accurate on the mpg. But the problem is, when my needle won't even move (very VERY bottom), I still have atleast a gallon in the tank. I was able to drive 15 hwy miles the other day when it was emptier than empty (the night before I ran out of gas pulling out of the driveway in the morning). So I suppose that I will just go until the needle doesn't even move, then divide the mileage by 15.5? Is that a fair assumption? This sure is getting complicated!

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

Total capacity is 62 liters, 16.38 gal. includes reserve!