4.7 oil pressure acting up
 

just bought a 2000 dakota 4.7 about a month ago and so far i love it, when i bought it the oil pressure was high but still well within usable range, while driving it sometimes dropped below half but still well within usable range but today i was at a stoplight and seen it was down and as i sped up after it turned green the oil jumped back up to over normal.(which is where it spends most of its time) then i realised as the rpms dropped so did the oil pressure gage till it hit its usual low spot and again after accelerating it jumped back up. should i be concerned? any ideas on what it might be? this is the first ive noticed of it so ill see if it does it again tomorrow

oh i did swap out the oil as soon as i bought it, its a little over the fill mark but like i said ive been running it for a month like this and this is the first ive noticed

Mine does that every time I change the oil, then a few weeks later it goes back to it's normal position (midway between the middle and hi hashmarks).

It's normal for the oil pressure to vary as the engine speeds up or slows down.

The question is, what is your oil pressure? If you can, put a mechanical gauge on it and see what its doing.

How low was the pressure? I'd be concerned enough to monitor the pressure.

it always stays between the hash marks and is rarely ever on the low end of the hash marks until just lastnight when it went practically from just above the lower mark to the higher one just from stepping on the pedal

Just to let you know; if you look around the forums this seems to be a constant defect of the Dodge Dakotas and really all 2nd generation Dodge Trucks; no matter the motor.

I'd keep an eye on it but not necessarily worry. It was in the "normal" range.

yeah its still doin it today, seemed to idle a little lower then normal too. anyway im swapping out the oil again within the nest 800 km's the old guy who owned it before me couldnt remember the last time he changed it and when i did it the first time it was pretty black, might as well get rid of as much of that oil as possible. thanks again tho

BINGO! We have a winner! Its impossible to diagnose this issue without first checking the engines OP with a wet gauge. If when the pressure is low and your not hearing any type of taping or knocking noises it should hopefully be the OPS unit. I've seen more than one OPS unit get a slug of sludge or get plugged that will cause this issue.

My 3.9L was fine during running but when i would let it idle the oil pressure would come right down. I took it in and the oil switch was shot. Could be that.

My oil pressure was dropping on my 3.9. i was going to change the sending unit, but I just wiggled the connector and the pressure has been staying normal.

I have heard on these engine that the oil passages a fairly small between the top and bottom of the engine and a little sludge can cause quite a problem by starving the top half of the engine. The prior owner being lax on changing the oil could be the cause.

so what should i do if the sludge is the issue? seafoam it?

That would be a start. The process is written up around here somewhere. It is usually pour a 1/3 in the gas tank, 1/3 in the oil and 1/3 down trickled down the brake vacuum line while running and cut it off and let it set for 30 min. It will hard start and smoke like crazy on start up if it is bad. You will want to change the oil within a couple hundred miles.

so swapped the oil out again this time with a more expensive oil (like it might help?) because i was goin through a timmies drive thru and heard a really obnoxious ticking coming form the motor! swapped it and seemed to be okay but now the tickings back ive heard everything about the 4.7 tick and now its really starting to get to me. i know i need new plugs i honestly dont think its been done since the last service it had at the dealship like 8 years ago, would this help any or am i gonna have to crack er open and swap out the lash adjusters and see if thishelps the noise/pressure issue

Swapping out the plugs will not do anything for ticking. Most likely going to have to swap out the lash adjusters and possibly the valves. Not real versed on this engine yet and it's problems but i know the valves can cause ticking on other model engines.

My 4.7 does both. I have the ticking on a cold start for a few minutes until the oil gets to the top of the engine, and the oil pressure fluctuates from the bottom normal hash mark to the top normal hash mark. Those lines signify the normal operating pressure ranges so as long as it's between them, I wouldn't worry.