I was coming up a steep climb on a very hot day and pulled over to take a break. When I tried to start it up again, it wouldn't crank. Just the solenoid was thumping. I had it towed home and in nearly 3 hours it still wouldn't start. Got up the next morning and it fired right up. Thinking that the starter got too hot, I built a shroud between the starter and the exhaust manifold. Could this the problem or should I be looking somewhere else? This is a 2001 F250 7.3 with an auto tranny.