The volatility also depends on the season. I the winter, they produce more volatile fuels for easier cold starts. In the summer, they blend lower volatility fuel to redce evaporative (sp?) emissions. So, if your car overheats in the winter, it may be more likely to face vapor lock. D^2 Quoting Christopher Hoffman <imperial67@xxxxxxxxxxxxx>: > Additives in modern fuel eat rubber, so fuel lines tend to soften and > weaken > and seals tend to degrade. It's advisable to replace all the fuel lines > in > any older car. > > Whether this contributes to vapor lock, I dunno. But the volatility of > modern fuel is different and that could cause it. Are you sure it's > vaporlock and not a collapsing fuel line preventing the pump from being > able > to suck fuel from the tank to the carb? > > I live in a hot climate and drive the car in hot weather and have yet > to > have a vaporlock problem in nearly 15 years, knock on rare genuine > walnut... > > Chris in LA > > Currell Pattie (currellpattie@xxxxxxxxxxx) wrote: > > Is there something about modern gasoline formulations that makes older > cars, > > like our Imperials with mechanical fuel pumps, more prone to vapor > locking? > > >