I drove a Volvo S60 T5 running LPG for a few months It was painful going back to petrol after that! I was getting the equivalent to 40Mpg in petrol terms, whilst still having plenty of power and comfort. I do not know exactly how long my Volvo was on gas, but I do believe it to be at least 30k miles as I saw the car for sale about 3 years before I bought it (115k miles on it now and no issues at all). I still have the car and just taxed it again this month.

I cannot tell the difference between running on gas or petrol other that the car feels like it has a little more go when on petrol. But you have to be flooring it to notice. The car switches between petrol and gas itself, so it really is no hassle. I cannot understand why there are not more LPG cars on the road here.

Only down-sides I can see:

- Spare wheel well tanks tend to be small and require filling up regularly.
- Large cylindrical tanks take up your boot. I have one of these, gets me nearly 400 miles range.
- Filling up takes longer than petrol and the pumps tend to be located in the corner of the forecourt, so you get wet when it rains!
- Finding cheap gas can be a pain in some parts of the country. I am lucky to live near a station which does not rip you off.
- Re-sale value will be affected, people find it hard to sell LPG cars I notice, but that means there are some bargains out there.
- Valve-seat wear. This will be engine dependent, some engines have suitably hard valve seats and are not greatly affected.
- Clutter in the engine-bay and quality of the workmanship is certainly hit and miss here.