I have converted a lot of ML's.
How many miles you get per tank will of course depend on which tank you have fitted and how you drive it. The usual tank option is a cylinder mounted underneath but some owners (where the ML isn't a 7 seater) choose to have a cylinder mounted inside. Where cylinders are mounted inside on MLs there will be a trade off between tank capacity and boot space for the owner to decide on,
Rough figures - Say you get 23mpg on petrol.. so you might get 20mpg on LPG, might fit a 70L tank with net capacity of 56L = 12.3gallions, so giving a range of 246miles and to fill the tank at 50p/L would cost £28. Replace figures with your own - how many mpg do you reckon you are getting on petrol now (subtract say 15%) and what tank will you be having fitted?
One way to look at it is that you'd be saving around £27 every time you fill the LPG tank (based on above figures).
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