I have a 2005 F-150 with a 5.4 Triton. It does have quite a few miles on it, 200,000, but it has always ran fine and I drive it every day. A few days ago I drove about 2 miles and I could hear a noise in the engine, then it lost all oil pressure. I immediately shut off the motor and coasted to a stop in neutral. After it had slowed down a little bit, I could easily hear something spinning in the motor and it was even a little "grindy". Then, just before I came to a complete stop, I could hear/feel something catch and the noise stopped on one side, but there was still another side making the same noise. A couple seconds later it caught and stopped. This was before I had made a complete stop. Then, I can restart the truck and it has regular oil pressure until I drive another mile or so. Any ideas? The local mechanic looked at it and said the oil pump was good and he couldn't find anything wrong with it.

Thanks

 

Engines don't make that kind of noise with out reprocussions of some kind

sounds like the phaser and cam tensioners giving up. I definitely would dig deeper to make sure.

did you change oil and filter afterwords? maybe take a sample of the oil and send it out to get annualized.....for comtaniates and particulates

 

This is just a guess but it could be you are losing oil pressure because the nylon pads on the chain guides have shreaded and dropped down into the oil pan. When the RPM's increase or you drive a distance the nylon shreads/pieces plug the oil pickup tube screen causing a pressure loss and the chain tensioners lose pressure allowing the timing chains to flop around making noise. You slow down the debris drops away from the pickup screen and pressure comes back momentarily. Obviously there are other things like the VCT system that can have issues with oil pressure as well but I have seen the pads shreaded and blocking pickup screens before. Your mechanic can use a borescope to look inside the pan and inspect for anything blocking the screen. Good luck.

 

i have seen these motors spin a bearing and cause symptoms like you are describing. drain the oil and look for bearing material floating in you drain pan.

 

mine did the same thing 4.6l yeah...dont drive it.....my engine seized on the way to the ocean....4000$ worth the repair....it aint fun. but yeah if u can drop the pan and check the screen. that was my problem

 

did your mechanic pop the timing cover and look at the oil pump? or just hook up an oil pressure gauge?? you may be getting pressure but no vol.

X2 on the bearings you might have chucked one and it might have got sucked up to the screen. and blocked oil. then when u shut the truck off it went back to the bottom of the tank.

This happend to my buddy.