^Best we've ever managed out of ours is about ~27mpg highway (@75mph) and 23mpg mixed. That's after thermostat, glow plugs, and module replacement. Worst fuel consumption was 21mpg and some change. Truck just went over 153,000 miles. Wish diesel fuel prices weren't on the rise as we love putting miles on the 35d.

Still much better than the mileage out of my 4.8 e53 which averages about 15mpg mixed and 18 highway.

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)