I agree with the other members. A hot no restart condition does lend itself to a high pressure oil issue. From my years of reading on the forums, the 05 HPO system tends to fail at the snap to connect (STC) fitting. This is the under the HPO cover at the connection from the HPOP to the branch tubes. Initial diagnostics will save you a ton of time and money. With all of my reading over the years, I have not found many issues with the low pressure oil supply on the 6.0's. The oil pressure gauge on the dash is a dummy gauge that is triggered by a voltage signal when minimum oil pressure requirements are met. My dash gauge will only register pressure after long cranking or after the engine has been started. Purchasing good gauge that can monitor the engine PID's
is the way to go before throwing parts at your situation. It will pay for itself on the initial repair.
An quick and simple check of the LPO supply would be to:
- Remove the oil filter.
- Use a ratchet extension to press down spring loaded oil drain back button. It is the black button inside the filter housing at the bottom.
- Have someone to crank the engine to see if the filter housing fills up with oil.
If it fills up, you have low pressure oil supply. You can then move on to diagnosing the high pressure side of things. This would involve checking the ICP for damage or leaks, monitor the ICP pressure, ICP voltage, ICP wire pigtail, and IPR duty cycle. With a good gauge, these can all be monitored with KOEO, cranking, and engine running. This data will let you know if there is a HPO leak in the system. These monitored values will be different if the oil is cold. If you have a small high pressure oil leak, the cold oil will not bypass a small leak and build high pressure quicker, thus the cold engine will usually crank. The viscosity of warm oil allows it to bypass your leak location easier, thus the hot no restart condition.
Once the HPO leak has been verified, you can begin the process of identifying the location of the leak by air testing the system. Knowledge is priceless. Keep searching and reading, and I guarantee you will save yourself some time and money.
Hope that helps some~