AdamW said:The fuel tank is 42 US gallons
I just had a thought. A mate of mine has a Clio dCi (1.5l new-fangled diesel). We went to Wales and back, despite the windy mountain/valley roads and carrying lots of gumph, it still averaged 65mpg.
So, converting those 42 US gallons into OG (Original Gallons) we get 35 UK gallons of whirling "derv"ishness.
35 gallons x 65mpg = 2275 miles in a tank! Obviously that is assuming the extra 125 litres of diesel weigh nothing
Still, I envy him. I get 320-340 miles out of a 45 litre tank of petrol in my Astra (400 miles if it is 100% motorways at 70mph), he gets over 500 miles out of his 35 litre tank no matter what he does.
Something worth doing with a fuel-hungry vehicle is reading the manual. I did this with mine, and read that for optimum economy I should keep the engine between 2K and 3K. I started doing this (using 3rd instead of 4th in 30 zones, 4th instead of 5th in 40 zones) and my fuel economy improved. It's not so quiet (you can't actually hear the engine if you keep it below 2K, passengers have accused me of turning the engine off at traffic lights in the past ) but hey, I'm saving trees!