ISX oil pressure problems

[Therealarw]

Hi everyone,

I got a Cummins ISX15 that’s been having some oil pressure issues. Only thing is I haven’t actually pulled the head off and actually dug deep into it. So the problem before I took it out of the truck was that the oil temperature would rise to 235 sometimes even 245 super fast. Oil temps would get to 235 during parked regens when it was 90-95 degrees outside. When we took it on several road tests it would hit 235 degrees on the temp and then the engine would lose oil pressure all the way to zero and would end up shutting the truck off. We even use a manual guage and it read zero on the road test. So it’s not electrical, my question is when I start pulling the motor apart where should I look? Is there certain oil galleys I need to look at? Do I just need to completely clean out the whole oil system? All suggestions considered because this is my first time dealing with this type of problem in an ISX15.

[SquareOne]

Whats the history on this engine? Ever rebuilt? Major repairs lately? What about mileage, engine type (i.e- CM871, CM2250, CM2350, CM2450), etc? We will need info before any suggestions can be provided.

Also, how long have you owned this setup? Do you have any prior knowledge on how the engine was treated before you ended up with it? What truck is it currently installed in?

[tree98]

Running it with zero oil pressure is a mistake!! You might have already eaten the bearings out of it. If it were mine I would hook up an external pump and push 30-35 psi of oil into the motor (engine not running) while looking at the bottom end bearings and cam bearings ( oil pan and valve cover off) you could be losing all your pressure through a spun bearing.

Actually you could find a spun bearing on the bottom end pretty easy just by removing the caps.

[Rawze]

(09-29-2023 )SquareOne Wrote:  Whats the history on this engine? Ever rebuilt? Major repairs lately? What about mileage, engine type (i.e- CM871, CM2250, CM2350, CM2450), etc? We will need info before any suggestions can be provided.

Also, how long have you owned this setup? Do you have any prior knowledge on how the engine was treated before you ended up with it? What truck is it currently installed in?

Agree... What make model?.. some history, etc.

also, what is the oil pressures at idle, and at 1500RPM, after the engine warms up to its regulated temp of 185-F?>

.. and what you are describing sounds more like the oil pick-up tube cracked, or pickup tube o-ring failing, and it sucking air ... maybe a failing oil pump... or perhaps simply not enough oil in the engine? .. but that is just a guess.

[Therealarw]

(09-29-2023 )SquareOne Wrote:  Whats the history on this engine? Ever rebuilt? Major repairs lately? What about mileage, engine type (i.e- CM871, CM2250, CM2350, CM2450), etc? We will need info before any suggestions can be provided.

Also, how long have you owned this setup? Do you have any prior knowledge on how the engine was treated before you ended up with it? What truck is it currently installed in?

We bought the trucks used about 3 years ago. There was a lot of stuff that wasn’t done on them as far as maintenance. I worked on them a lot just to get them all back into shape. The motor that’s in it is a CM2350. It had a camshaft lobe go flat on it in a couple of spots. Put a new camshaft in along with new cam bearings and some of the rocker arms that were starting to pit on the rollers. Fuel pump camshaft had gone out on it also but the oil temps getting hot was happening prior to the fuel pump going out.
I currently have it on an engine stand and I put a motor we had out of our wrecked truck put in the truck with the motor that was overheating.
I ended up pulling the #4 main bearing cause I had actually put mains and rod bearings in 2 months prior. There was some scoring from the fuel pump camshaft I’d imagine. But I recently pulled the #4 after I got it out and it wasn’t on the copper. Even had the dealer do an oil sample and it came back clean. Also weirdly enough we were able to drive the truck Bob tailing it and it never lost oil pressure, once we had it hooked up to a trailer and loaded is when oil temps wpukd rise up and once it hit 235 on oil temp while driving it just completely shut off.
40-45 lbs of oil cold. Once it warms up it drops up to about 20-24 psi. When you’re on the throttle it shoots up to about 38-45 lbs of oil. Engine has never been taken apart it has about 800,000 miles on the motor. So the only thing I haven’t really done was actually pull the head, pull the pistons/ liners out etc. so that’s what I was wondering was the way to go about getting everything cleaned out. It seized up the turbo twice. And so that’s why we stopped messing around with it and used a different motor. Now everything is working fine on that one while on my free time I plan on going through the overheating one. Coolant was also staying at 185 constant, would only get hotter if the driver was pulling a hill
List of what was done to it.
Camshaft
Camshaft bearings
Couple rocker levers
Oil pump
Main bearings
Rod bearings
A couple of turbos
Oil cooler
Oil thermostat.

[Rawze]

A bad delete program can easily cause the engine to overheat the oil like that on a whim ... though it would not cause the zero oil pressure.

That may be a heavy contributor of the the oil temp issue part of it any ways. It should be around the 218-220~ish F range unless your in a hard pull.


and if someone changed the cam bearings in the head, then that could be a place for some problems. The factory bearings opening are often set slightly offset on some of the lobes to help balance oil flow across the rockers, etc. - If they aligned all of the oil passage holes perfectly, then this could be one place for it to bleed excessive oil .. but I doubt that it would be more than a psi or 3 at most for that alone. - Improper clearance though due to incorrect bearing sizes vs. the cam lobes, or one that got spun, .. and that could be a definite culprit for sure.


Also,.. at 185-F the oil pressure gong down the roads (above 1100 rpm) should normally be about 32-34 PSI.. so if it is only getting to 24-psi that is a serious issue. and at Idle, it should be above 18 minimum.. but typical is more like 20-24 psi at idle alone... depends on idle rpm.

[tree98]

Am I understanding you right........ you said this engine had a fuel pump failure?

[SquareOne]

(09-29-2023 )tree98 Wrote:  Am I understanding you right........ you said this engine had a fuel pump failure?

Exactly what I was thinking...wonder if the oil overheating issue is a result of the engine not being flushed properly to remove all the metal pieces.

[Rawze]

(09-29-2023 )SquareOne Wrote:  

(09-29-2023 )tree98 Wrote:  Am I understanding you right........ you said this engine had a fuel pump failure?

Exactly what I was thinking...wonder if the oil overheating issue is a result of the engine not being flushed properly to remove all the metal pieces.

They did mention that it had a fuel pump failure ...

If that fuel pump (or other hardened component) failed and sent metal thru the engine ... your f$ucked without ...

A== Some kind of serious deep-cleaning flush with several hundreds of gallons of diesel-oil mix going thru the engine while it is run.

B== Pulling and inspecting a few (and not just one of each) of the rod and main bearings to see how extensive the damage is to the bottom end, wrist pins, etc... because it will be be inframe city if there is.

B== Inspecting all of the face gears and replacing all of them that may have gotten pitted.

C== Replacing the oil cooler, oil filter, AND cleaning out the the oil bypass valve. The oil cooler will be full of metal shavings, and there really is no way to get them all out. The engine will spit out metal into the oil system randomly and fail all over again if it is not.

D== Pulling the rocker shafts and rockers apart, flushing all the tiny passages in each of the the rocker arms, cleaning the passages in the cam, etc.

E== Pulling the face gears and cleaning behind them, and also, while the oil pump and rocker shafts are off of it, flushing the passage between the front gear housing cover and the block that leads to the oil pump pressure regulator.

D== The injectors and several fuel system components will also need replacing if the plungers are damaged. Injectors, high pressure relief valve, and the fuel rail + all fuel system components needs to also be flushed too.

- It is VERY VERY COSTLY ... a whole lot of flushing and work has to be done to it ... and time consuming to get the engine back into a reliable state and to stop all of the progressive damage after the fuel pump fails. This especially if some moron kept driving more than a few hours ... or worse, a few days or more with a bad fuel pump!.

so ... most likely... and for all anyone knows, the oil pump and a whole lot of other things could be destroyed too. This could also explain the oil overheating, and that the pressure is way off, as a whole lot of metal shavings typically gets caught into the oil cooler, clogging it up, and the passage feeding the oil pressure regulator gets full of metal too.

I.E.> THE ENTIRE ENGINE BECOMES A BOAT ANCHOR AND IS DESTROYED whenever that fuel pump fails and someone keeps driving it against the 0559 (low fuel pressure) fault codes that come and go like the wind, and they ignore them.

That or they go more than 400k miles (8,000 hours) without changing the guts of the fuel pump!.

I SERIOUSLY THINK THAT THE RED ENGINE MAKER SHOULD HAVE A BIG DAMN FAT ORANGE AND YELLOW STICKER ON THE SIDE OF THE ENGINE .. That says to replace the guts of the fuel pump every 8,000 hours or 400k miles regardless of condition ... really I do!.