04 Ram 1500 4.7 oil pressure drops

04 dodge 1500 4.7. New oil pump new bearings new O.P.S twice .but oil pressure drops when i stop or idle.i touch the gas and it goes right back to normal but no ticking nor knocking engine runs smooth. I put a manual gauge on it and it does the same thing! Could it be slug built up in the oil pick up tube? Also changed the oil like 3 time in month no metal no burnt smell or nothing voltage is good and the ohms on the O.P.S is good and the plug is good no wire frade or cut.

How low does it drop at idle and what is your idle RPM's?

NYCruiser said:

How low does it drop at idle and what is your idle RPM's?

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Well it doesn't drop slow nor fast it just drops and idle is normal around 600 to 700

I'd say a sudden instant drop is pretty fast... LOL.

Where do you live (which US state or Canadian province)?
What oil grade are u using?

When you say new bearings, which ones?

xb1230 said:

I'd say a sudden instant drop is pretty fast... LOL.

Where do you live (which US state or Canadian province)?
What oil grade are u using?

When you say new bearings, which ones?

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Lower east US and I was using recommended 5-30 now I use 10-30 either way still the same and the motor is new bought the truck and the motor was just installed but he ran it hot and I had to change the head gaskets and went ahead and changed the timing chain just in case inspected oil pump just to be sure and its new also have paper work motor hasn't hit 15000 miles yet and I have paper work that proved that

Harry5o said:

Well it doesn't drop slow nor fast it just drops and idle is normal around 600 to 700

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I don't mean how quickly it drops. LOL I mean, what pressure does it drop to. 0?

Getting a higher grade oil can actually worsen this issue. Try getting molasse up a straw... hen water... You get the picture.

The 4.7L is actually very picky when rebuild on the bearing races on the Crank. Depending on how it has been rebuilt may very well be the root cause of your oil pressure issue.

There are 3 factory sizes for the 5 bearing races of the crank and they are stamped on one of the crank counter weight in the order they should be going in. Also it would seem there is a great deal of problems getting good undamaged bearing for the 4.7L due to the original Chrysler Packaging. If unvalidated Damaged or the wrong bearing size was used for rebuild by an unknowing or careless tech, you could be facing these oil pressure issues and the bearing could already be shut even at 15k miles on the engine.

THat being said, if you have paperwork for the rebuild engine, isn't there a warranty on the rebuild? I would take the engine back to the rebuilder and have them take a look at this.

You will find here the Service Manual for you truck. On page 1358 of 2627 you will find the information on the crank's main bearing selection chart and the rebuild information.

Here is a video playlist of a 4.7L rebuild on Youtube where the fellow doing the work talks about the challenges he had getting undamaged bearing for his rebuild from dealers... The first video in the playlist will describe a very similar issue to yours...

Hope this helps.

Well the motor came from Napa auto parts basically a long block. Stated all new bearings and stuff to eliminate them because I know there good but I heard the pick up tube could be choking it because people say these engines are bad about slug. I've already had to replace the lash adjusters because of it.

Yea NYCruiser the manual gauge reads 0 give it gas and up to 50 she goes lol

Hard to believe the pressure could actually be dropping to zero and the engine not making any noise.

If the issue is sludged up pickup tube, you would alleviate/lessen the issue with a lower grade oil. The newer block run 5W20 which would be a little lighter and easier to syphon through the smaller hole.
It might be worth trying if only for troubleshooting purposes. If you try the 5W20 route try an oil with lots of detergent in it or maybe even an aggressive engine flush. That would help get rid of the potential sludge.

That being I fail to understand why you would have had to change all of those parts on a 15k miles rebuilt engine. Unless the rebuild was very sloppy, a rebuilt engine should have been completely cleaned and free of any previous sludge... the 4.7L is bad for sludge, but not that bad...

NYCruiser said:

Hard to believe the pressure could actually be dropping to zero and the engine not making any noise.

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If I could post a video I would show you everything

Harry5o said:

If I could post a video I would show you everything

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maybe its the oil pressure port that's sludged up.

I'm just trying to get it fixed where it's works for a day or two so I can trade it in lol this truck takes my wallet every friday