18.5 or 21? - The Unofficial BMW M5 Messageboard (m5board.com)

Need4Spd · 29th January 2001, 05:17

No, I'm not talking about driving, drinking or other ages! How many gallons does our tank hold? The spec. says the capacity is 18.5 gallons, and that there is a 2.5 gal. reserve. Does the 2.5 come out of the 18.5 or is it in addition to the 18.5 (hence, the 21)? It seems I put in about 15 gals. when the fuel gauge needle is at 1/4, so I'm thinking that the 2.5 is in addition for a total of 21. Doesn't the light come on when you're at "E" and then have 2.5 left? Of course, maybe my calibration is off. Also, every magazine article I've read on the M5 puts the fuel capacity at 18.5, but I'm wondering if they just didn't count the reserve either?

robert47 · 29th January 2001, 05:30

Wish I knew the exact amount as well. For fun check our the messages on gas tank "leakage" on this site; http://www.84to96.net/kaleco/gm.htm

bobafett · 29th January 2001, 07:36

what reallypisses me off is how inaccurate the godforsaken mileage guage is on the OBC.

--Dan

A-Train · 29th January 2001, 16:54

The 2.5 gallons are part of the 18.5 capacity, not in addition to, so you can use 16 gallons before the light turns on, theoretically.
- A-Train

Teutonaddict · 30th January 2001, 01:15

I'd put total capacity at 18.5. BMW's fuel gauges are notorious for their non-linear calibration (longer time at 'full' range, more quickly through the 'empty' end of the scale). While I've not run out of fuel in this vehicle, I seem to remember doing so on one of my prior 540/6-spds (E34 or E39--can't recall which), and it was just past 18.5.

c4m5 · 31st January 2001, 01:22

Today, the light was on, the OBC said range 10 miles, the car took 19.1 Gallons and I over filled (no spillage). 18.5 seems to be correct. DG

Need4Spd · 31st January 2001, 08:04

Oh, well, I guess this just means I get to stop at the gas station more often and be able to look at my car from the outside!