Thought I would turn to you guys for a little help. Cam phaser was bad on the drivers side. So after tear down went ahead and put new timing chains, guides, and tensioner. Then I installed a new cam phaser on the drivers side. Also put new camshaft position sensors in. The drivers side was the only one making any noise. Now the passenger side is making the noise and the oil pressure drops to zero at higher rpms then back up when you let off the gas. Hope this make sense and I am trying to keep it short. Thanks for any help.

 

My '06 had intermittent cam phazer problems when I first bought it. After the dealership finally replaced the phazers it gave me the same problem on the drive home. I never noticed a dip in oil pressure, but after ~2 weeks back at the dealership they finally (realized? admitted? discovered?) the crankshaft had too much end play causing a dip in oil pressure that was the root cause behind the cam phazer problem.
The way I understand it, the cam phazers work off oil pressure, so a slight loss in pressure can cause one or both to retard when they should be advanced. This was causing my intermittent rough idle.
I know it's not good news to hear you might need a new engine, but it's better than wasting hundreds of $ and weeks or months of your life.

 

slo5oh, Thanks for the reply. Wouldn't you think that low oil pressure would be more constant? The oil pressure drops for about a second and fine for awhile. I do agree about wasting $ and life. Been a real pain. Anymore thoughts on this would be great.

 

Keep in mind I've never torn down a 5.4 so my ideas here are based on my 5.0/5.8 experience.

Loss of pressure at high RPM seems very wrong to me... the only obvious things that come to mind are:
something blocking your oil pump screen
failing oil pump

When you had it apart for the phazer did you notice any sludge in it? If so I'd run a good full synthetic (redline, mobil 1, royal purple, amsoil, etc) for a while to clean all that out. The reason for running a full synthetic is because they have MORE detergent. I don't know how this oil pump is designed, but in the ones I'm familiar with have a valve that opens up at higher RPM to bleed off excess oil pressure. Think of it like this, at idle you see something lower like 30 or 40lbs as you increase RPM the pressure climbs, usually spiking at around 60lbs, somewhere between 2k and 4k rpm. The reason for this is that 10lbs of pressure for each 1k rpm is all that's really needed, higher pressure is actually bad unless your engine was designed for it. That's part of the reason why common weekend/street racers replacing their standard volume/standard pressure oil pumps with high volume or high pressure are just shooting themselves in the foot. Higher volume is only a benefit if you have a larger than stock oil pan, higher pressure only if you run loose bearings that require the higher pressure.

 

Thanks again slo5oh. I am at the point I have to agree on the screen. Just tore it all down again and removed the oil pump and tried to blow air thru the pick up tube. Do get some back pressure on the tube. I am hoping to get it cleaned. I didn't take the pan off due to "alot more work". Pretty much remove the front end. There is some build up in the engine so I will try what you said with the oil. Thanks again for responding.

 

That's not a good way to remove sludge. Use AutoRX, and follow the procedure on their website exactly.

 

My04150, take a good look at the drain holes in the heads. They are small and are designed to work with a specific viscosity fluid- 20 at temp or 9.2 max at temp. What you may be experiencing is the oil is being pumped into the valve cover faster than it can drain back into the pan at high rpms. If they are sludged any at all, there's yer problem. Skip the tricky oils, they have no more detergent than any other and the current base oils have no more solvency than anything else out there with one and one only exception, G Oil. The ester base naturally has more solvency and the newest formulation is loaded with additives. If you want a darn good synthetic, G Oil is it. And don't sweat the 5w-30 as it's on the thin end of the Kinematic scale just barely over the 20 viscosity rating. Or to better say it, you or your engine will never know the difference except it will run a lot cleaner. With trending analysis you should be able to run G Oil, current formulation, 10,000 miles if you like.

 

glc and Labnerd, Thanks for the reply. There is some sludge so I will check the drain holes closely. At this point I will take all responses and try what I am being told. I will let you all know how is goes. Thanks again