I do not imagine it is hot gas (petrol) returning to the tank causing the fuel pump failures. Any hot fuel returning to the tank will be cooled by the volume of petrol in the tank any way, over an extended period the fuel temperature in the tank will obviously rise a small amount, it would be easy to check with an infrared temperature gauge after a long run.
The fuel pumps are from a Land Rover Discovery and would have undergone extensive hot weather testing.
Last edited by Rog G; 21/06/18 11:04 AM.