Heat causes gasoline to boil in the fuel lines and cause vapor lock. This is nothing new. And cooling the fuel lines helps. However, E10 is more volatile than the gasoline these engines were designed. And this is the time of the year when refineries are switching to winter blend fuel and volatility is more common during the transition period. Phase separation is caused by alcohol's affinity for water. Phase separation occurs when the gasoline water content exceeds the maximum amount of water the fuel can dissolve, and the excess water drops out of the solution to form a gasoline layer and a water layer. Phase separation is temperature sensitive, but cooling the line will not fix the problem. Only keeping water out of the fuel supply will fix phase separation.
