2004 f150 5.4 runs great for about 10 min.
After about 10 min. Oil pressure will drop to zero then come right back up. It will do this a
few times then sound like a deisel. Oil pressure will stay down after a while until I
If it is clattering like a diesel then you have an oil distribution problem. Check the pump.
Thanks for your answer Mark. I was kinda thinking along those lines, just found it odd that oil pressure would be good until it runs about 10 min. These motors are notorious for issues of this type and not sure if it's a cam phaser deal or what
The cam phaser operation operates on oil pressure. When these engines get many miles on them the oil pressure at idle is lower than designed and this causes issues. I have read that using a 15w40 oil will help, but I do not recommend using oil other than what the manufacturer specifies. Also it is possible that you have a partially clogged oil pickup screen. This could be clogged by sludge, insides of a defective oil filter or debris from the cam tensioner rubbing blocks. In any event this needs to be addressed as you are risking damage to the top end of the engine where the camshafts and valve train reside.
It's just hard to wrap my brain around the fact that it starts and runs like a champ for 10 min. Oil pressure is,great unt it does that sudden drop, picks back up almost instantly. Even when it flatlines it still picks up when acceleration. So I think between first checking the pickup screen and flush, oil pump is next. I guess changing the oil pump would be a good time to change cam phasers and chain. Any insight on cam bearings at this point?
No cam bearings, they are a machined surface that is part of the cylinder head and cam retaining caps.
How is this issue repaired if can't change bearings?
Possibly a new oil pump if it is worn or an engine overhaul to put clearances back to factory specs. If the oil pressure is the problem a high output oil pump may solve it. I have a friend that has the same exact problem. He has thrown some parts at it, but been unable to fix it and he just drives it. When he brings up the rpm it is fine.
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