mercedesbuff

I never run my cars even close to empty (usually fill up above 1/4 tank). But, one particular day last week, my wife came home and said "the fuel light is on" and that she'd had a busy day and asked if could I please fill up her car in the morning. The next morning, before I got in the car, I checked the M-B Connect App, and it showed fuel level at 3% (grrrrrr)... I climbed in the car and the "Range" no longer displayed a mileage estimate, just a yellow "Your-wife-is-out-of-gas" hieroglyph.

The fuel gauge showed only one very small yellow segment, so I knew I still have a tiny bit of "reserve" in the tank. I set out on the 10.5-mile route to Costco. At some point along the route, I noticed the small yellow segment had disappeared from the fuel gauge, leaving a totally empty display. Yes, I'm sweating at this point... I'm also looking ahead for easy places to pull off, in case the car dies, while silently wondering how long M-B Roadside would take to dispatch me a few gallons of gas. But at last, I pulled up to the gas pump with no hiccups (phew)!

I'm a numbers nerd, so I remembered that my GLS had a tank capacity of 23.8 gallons. So you can imagine my shock when I noticed 24.035 gallons had been dispensed, when the handle shut off automatically (I never top it off).

So I came home and double-checked the official specs on the MBUSA Media website, which says:

Then I looked in the owners manual, which says:





So, how much fuel have you pumped into your X167? Am I the only one with an anomaly? Do I need to have words with Costco, since their pumps are apparently a tad "optimistic?"

Some other explanation? Are the Germans being truthful (hehe)?

Thanks in advance for humoring me...

EWL5

I've always been told there's more in "reserve" but it's not going to be a lot. You may have just tapped into it!

SW20S

I think you were just way, way empty!

mikapen

I think you're right.

What he did was to measure the capacity of the filler neck only, which probably isn't included in tank capacity.

wildta

This reminds me of that Seinfeld episode where they drive the car to empty.

z28lt1

Lot's of variables here:

• The Tank capacity at 90L might be rounded a bit
• As noted, the filler neck and such are not included in the tank capacity, so you can get more in than the tank capacity
• Temperature has a noticeable impact on gasoline density (about 1% for every 15 degrees) so a cold day could versus hot day could change the capacity .5 gallon or so. Of course, the tanks being under ground make it much less of a difference than the ambient air temperature, but if you live in a cold area, you can get over capacity for sure (and perhaps less on a hot day).

mercedesbuff

Interesting... Thanks for adding this. I hadn't thought about applying actual science. It was a cold morning, around 20°F.

mercedesbuff

I hadn't considered the filler neck before... Thanks for adding that. Maybe Costco's pumps are accurate, after all. I must've been seconds from empty... (I really was sweating).

SW20S

Bear in mind too the pump never clicks Off at the same amount each time