Exactly! All Johnny has to do is find some cover and heat the tanks while Pyro searches for him.
Consider this (part 01): If Pyro uses gasoline in his tanks, he's screwed. Why? Unleaded gasoline has a certain percentage of water. Since Johnny can also lower temperatures, all he has to do is lower it enough to freeze the water in the gas, and the tanks are useless. However, if Pyro uses another sort of fuel, this might not work.
Consider this (part 02): Johnny can extinguish any flame (whether he's aflame or not), so the vice would be snuffed out before it even touched him.