Hello, and welcome to Just Answer. My name is ***** ***** I will assist you with your question.
The fact that it will not start when hot tells me that there is still a leak somewhere in the High pressure oil system. Basically what happens is the PCM needs to see 500 psi in order to turn on the injectors, since it is not seeing this it simply cranks but wont start.
What I will recommend is that you take off both valve covers, and get the special tool that screws into one of the oil rails on top of the injectors and apply air pressure to the High pressure oil system and see where it leaks at. If there is a leak in one of the cylinder heads it will be easy to fix at this point. If the noise (air leak) sounds like it is in the center of the engine
, it will be down there somewhere. Depending on if your truck is a early or late 2004 (depends on if the ICP sensor is on the valve cover or still at the back of the engine), The setup of the High Pressure pump is not the same and uses a different way to connect it.
If all of this checks out ok, then most likely the issue is the branch tube that the oil pump sends oil thru to the heads. In order to change it the rear cover of the engine will need to come off and you can undo the 2 bolts where the stand pipes go in to the branch tube carefully and not loose them, otherwise the heads have to come off as well. It is not a easy repair and certainly not something that I would recommend to do at home in your driveway. Needless to say the transmission
must come out to get the rear cover off of the engine.
If you need more information or have more questions, just respond and I will reply just as soon as I can.
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