Some idiot fitted an under-slung tank to my van before I purchased it but what a botch job they did you would not believe. They welded angle iron to the chassis so now it can not be removed for maintenance, fitted a filler pipe made up of several bits including what looks like a bit of "Hoover" pipe which leaks when you fill it . also leaks from the top of the tank but with only an inch between the tank and the underside of the floor it's impossible to see why. Didn't connect the sensor so you have no idea how much is in the tank but the most stupid thing is they didn't put a drain on it so there is no way to empty it. No insulation means it will probably end up being a giant ice cube when the weather turns cold. be aware, ,they walk among us, idiots I mean.