Q - Hi, I was reading one of your articles and see that you have had good luck with the 6.0 I have a few questions for you. I don't own but but over the last year my uncle and brother have purchased a truck each and have had issues. I do alot of work on vehicles but haven't had a chance to learn these engines. They have taken them to a few shops and I can see where every word your wrote was spot on some of the things they were told. After spend loads of cash for repairs they still have issues. I would like to just ask a question about each engine to address the problem they have now. 1. My uncle recently to his truck to a local shop to see what was wrong with his heat since it has turn cold. They find he has no thermostat so they put one in and the truck wouldn't pull it self a total loss of power so the fix was they removed it and the truck was back to normal power and he picked it up. I found that to be strange so that's when I found your article, how could putting a thermostat in cause that great of a difference? Does he have a major underlying problem that has been masked by removal of the thermostat? 2. My brother has had the works done to his, yes the imfomus total injector replacement and it did help but he had to go back a few times. Now he still has one of the same issues he started with. Cold start is great runs fine but once you reach your destination and the engine is hot after the trip the truck will not start at all, you can either wait it out or ha e someone pull you or park on a hill to roll start. This truck is a 450 so it doesn't roll easy. Lol so the question is what could make it have a hot engine start issue? Hopefully these 2 question will be somewhat easy explained but I do understand it may not be that simple. Thank you for any advise you can give me. Mike

A - 1. I don't think the thermostat could have anything at all to do with the lack of power you are describing.  I would sooner believe that they left an intercooler boot loose or not tightened properly when they moved it out of the way to change the stat.  Then we they took it back out they reconnected it.  Also, leaving the back pressure sensor or maf sensor unplugged can lead to no power issues as well.  I'm betting its one of those things.

2. He has a high pressure oil leak somewhere in the system.  I would check the stand pipes and dummy plugs along with the STC fitting for a leak.  It's also possible to have a leak on one of the connections from the oil rail to the injector.