Constant low oil pressure after top rebuild

[Dangitdodge]

Hoping for some suggestions. The shortest story is its a 2014 2500 6.4 Had the camshaft thing happen at 170,000. Out of warranty of course and during covid. Had the dealership rebuild the top end and replace the oil pump sense they already had it apart to diagnose and it was during the worst of the parts shortage time with no other options. All new oem parts. About 1,000 miles later we had check engine light. Took it back they checked it said their work was fine saying the oil pressure was a little low but they'd done everything they could. Said was because we didn't rebuild the entire thing, that perhaps some debris had come thru and stopped something up. Suggestion was that it was pumping all the oil into the top and it couldn't drain back thru fast enough. We were hoping it would flush out with oil changes. We've questioned if it really was running low pressure at all. Now it starts up totally cold with about 20 psi. Quickly starts dropping. (Confirmed with a mechanical gauge) Will run at average 18psi while driving 55ish but as soon as you stop like a stop sign and idle, it'll drop to 4/5. No sounds, nothing over heats, oil temp stays at about 220, no performance issues. You'd never know anything is wrong unless you looked at the gauge and the dash light/codes. It will shut off when you suddenly stop after about 30 min of driving (like it did last week to turn off the highway) This is the safety mechanism because of the low pressure. But will restart after a few minutes with same conditions and no odd sounds. Done several oil changes with different oil filters and the oil pressure switch. Nothings made any difference. Towed it back last time just to be safe and changed oil next day. No metal in the oil or filter material. Oils normal, no discoloration. No tapping, knocking or any sounds to indicate the engine is starving for oil. Is it possible the passage for the oil pressure sensor is partially blocked? Is there another place we can put the mechanical gauge besides the oil pressure sensor port? We've just seen the idea on here about changing to a heavier weight oil instead of the 0w40 that it calls for. Going to try a test run on the newest oil filter and then a different oil weight if nothing changes. Is there anything else we can do/check without giving in and taking to a shop and spending $$$$ to take the truck apart again to drop the pan and see if they can tell anything?

 

[Sherman Bird]

I'd think maybe checking the oil pump pick up tube/screen/o-ring would be the next thing. Otherwise, there is too much clearance in the workings of the engine to obtain higher, normal pressures.

As a side note, the 5.4L 3-valve Triton engine in Fords had/have similar problems with high mileage. Replacing the stock oil pump with a Melling high volume issue corrected those problems most often.

I hope this insight helps!

 

[Dangitdodge]

I do appreciate it! We tested a new Mobil 1 filter and fresh 0w40 and it's actually worse. Started up 30 but immediately started dropping. At 50 mph it was running 11 and dropped as low 3 pulling into the parking spot. Spent 20/30 minutes in the store and it restarted at 10 and immediately started dropping.
As another test we are going to drain the new oil out and try a heavy weight. Any suggestions on what weight to try?

 

[Dean2]

A high volume oil pump from the Hellcat and other performance 6.4s would be what I try. It seems very suspicious to me that you put in a new oil pump and now have pressure issues. I really don't think this is an issue with something being plugged up and I really doubt lack of flow to the sensor is causing a low read on both the truck and the mechanical gauge you used.

 

[DILLIGAF]

Yup any Performance shop would of put a HC oil pump in it. But your mistake was taking it to a stealersh!t for repair.

 

[Dangitdodge]

But your mistake was taking it to a stealersh!t for repair.

yeah I know! But we really had no choice at the time. Covid had everything so messed up. Dealership said they had a wait list for new engines and would be months before we'd get a new one, no remans were available either. Plus the parts shortage so they had more access to stuff then anyone else. Still took them a couple weeks.

 

[Wild one]

yeah I know! But we really had no choice at the time. Covid had everything so messed up. Dealership said they had a wait list for new engines and would be months before we'd get a new one, no remans were available either. Plus the parts shortage so they had more access to stuff then anyone else. Still took them a couple weeks.

If it had good pressure before hand,i'd be leaning towards the O-ring on the pick-up tube as Sherman stated.It's easy to tear it on re-install of the pick-up tube

 

[jws123]

Like others mentioned the o ring on the pickup But while your in there just change the whole pump while you are there unless you want to do it twice also stop running it until its fixed.

 

[GTyankee]

First thoughts ...

I am leaving the oil pump out of the equation
Others have covered that possibilty

Your Motor Oil is already 40 weight, 30 weight is plenty for a gas powered engine.

Forget about the number before the W
W is a shortened form for WINTER
The number before the W, means that at ZERO degrees F, the oil will begin to move through a port of an engineered size

0W means at zero degrees, the oil will start moving through that small port or hole
5W means using that same flow test, the oil starts flowing at 5 degrees F
10W start flowing at 10 degrees F

...........................................................

the number after the W. is the weight of the the oil, measured at 100°F

so using your current Motor Oil
will begin flowing at ZERO degrees F
the 40 weight motor oil is an SAE tested at 100°F

IN Maryland, it does not get Too Cold or Too Hot

I would try 0W-30 or continue using 0W-40

If 0W- is not available, 5W- would work in Maryland

 

[Dangitdodge]

Just for S**ts and giggles we ran 15/40 and it gained about 4 lbs at 50 mph but still drops down to 4/5 when stopped. Everything was the same as the other oil. So gonna go ahead and make an appt somewhere other then the dealer and will go ahead upgrade to the Hellcat pump sense it'll already be apart. We tow a lot so the upgrade makes sense anyways. Is this what I'm looking for in the link below? and will we need the pickup tube as well?

https://www.mymoparparts.com/oem-pa...wJnk9MjAxNCZ0PXRyYWRlc21hbiZlPTYtNGwtdjgtZ2Fz

 

[Wild one]

Just for S**ts and giggles we ran 15/40 and it gained about 4 lbs at 50 mph but still drops down to 4/5 when stopped. Everything was the same as the other oil. So gonna go ahead and make an appt somewhere other then the dealer and will go ahead upgrade to the Hellcat pump sense it'll already be apart. We tow a lot so the upgrade makes sense anyways. Is this what I'm looking for in the link below? and will we need the pickup tube as well?

https://www.mymoparparts.com/oem-pa...wJnk9MjAxNCZ0PXRyYWRlc21hbiZlPTYtNGwtdjgtZ2Fz

I think that's just the standard volume pump,you want the oil pump that fits the 6.2 not the 6.4. Your pick-up tube should work as long as it's clean. Change your listing from your 2014 truck,to something like a 2019 Hellcat

Hellcat Oil Pump

Hellcat Oil Pump

www.modernmusclextreme.com

2015-2023 Mopar Engine Oil Pump 68195993AD | My Mopar Parts

2015-2023 Mopar part # 68195993AD - Engine Oil Pump

www.mymoparparts.com

 

[Wild one]

If you do decide to spring for a new pick-up tube,you want the pick-up tube for your truck.The oil pans are differant between the cars and trucks,and the Hellcat pick-up tube won't work with your trucks oil pan. A TRX's pick-up tube might work,but i'm not sure if the TRX's oil pan is the same as the 6.4 trucks pan,so to be safe just get a replacement tube for your truck

 

[greg mayrhofer]

it is possible your head gaskets are not aligned, maybe restricting an oil passage or dirt from cleaning the head got into one passage or two

 

[Bandit1859]

Just for S**ts and giggles we ran 15/40 and it gained about 4 lbs at 50 mph but still drops down to 4/5 when stopped. Everything was the same as the other oil. So gonna go ahead and make an appt somewhere other then the dealer and will go ahead upgrade to the Hellcat pump sense it'll already be apart. We tow a lot so the upgrade makes sense anyways. Is this what I'm looking for in the link below? and will we need the pickup tube as well?

https://www.mymoparparts.com/oem-pa...wJnk9MjAxNCZ0PXRyYWRlc21hbiZlPTYtNGwtdjgtZ2Fz

If not soon it is going to blowup or do more damage from lack of pressure

 

[Casper]

I hope for your wallet that the cam/lifter failure didnt send debris tracking through one of your main bearings. That would cause a psi drop noticeable at idle that the oil pump might not be albe to keep up with. It would probably get worse the warmer the oil gets.

 

[Dangitdodge]

Just to follow up with an update and to quote the repair shop "the motor is toast" a low milage used installed is going to cost $11,000. They did not recommend a reman said they are seeing lot of problems with those.

 

[Dean2]

Just to follow up with an update and to quote the repair shop "the motor is toast" a low milage used installed is going to cost $11,000. They did not recommend a reman said they are seeing lot of problems with those.

Sorry to hear that. Really does suck the Big Magilla Gorilla when you get that kind of news.

 

[jws123]

Just to follow up with an update and to quote the repair shop "the motor is toast" a low milage used installed is going to cost $11,000. They did not recommend a reman said they are seeing lot of problems with those.

A decent used engine should be no where near 11k installed LOL its a very easy engine swap takes 4-5 hours check local junk yards $5500 for a good motor $1000 TOPS install stay away from dealers and that shop. If you where local to me bet I could fix the current engine for waaaay less maybe try to see if you have any local machine shops.

 

[DILLIGAF]

11k gets you a 6.4L from MMX.

Those guys are trying to screw you at that price.

 

[Dangitdodge]

We have asked some other shops for quotes to compare. Waiting for responses. Im not dumping that kinda money into something without a warranty so just hitting up a junk yard isnt going to work. Just googling is giving 10-12 hours of shop time and prices in the 6/7 thousand range for a motor. The shops quote was a used one with 35000 miles on it with a warranty. Ill report back on the other quotes when we get them.