Why is my oil black?

[Waterloo]

I figured it would be black for a couple of oil changes after the in frame, but it is still black?

There is a puck in the EGR cooler exhaust. The Venturi is blocked, going to remove and double check, so no air should be going to or even through the EGR valve, correct? Or am I missing something?

I did an overhead yesterday, haven't started the truck yet as it is still apart on the intake side. Head looked clean inside, cams and rollers good. Nothing weird found in there.

I use Rotella and a gallon of Sta-Lube, new air filter, turbo looked very nice internally, CAC seems to be a ok, no signs of an air leak, truck runs as smooth as a sewing machine.

When we assembled the motor, everything was cleaned out, no soot anywhere in that motor when we closed it up, but that oil stays coal black.

Thoughts?

[Rawze]

if u idle a lot it will stay black.

[Waterloo]

No idling, tri-pac. I pulled the Venturi, and it is still sealed nicely. Now, the differential pressure sensor, center pin is clipped, but I blew air through it, on the intake side, front of Venturi, air passed through it to the back side, EGR side of the DP sensor. Should that not be closed, so that air cannot get through the sensor? Or does it close when power is applied?

I sealed the holes in the DPS, its not functioning so what the heck. Used the red RTV and put her back together. Found the heat Shiel on the EGR valve rotted away, so I ordered a new one, not much left of it. EGR valve body looks good. See no need in taking that off.

[Rawze]

(10-08-2019 )Waterloo Wrote:  No idling, tri-pac. I pulled the Venturi, and it is still sealed nicely. Now, the differential pressure sensor, center pin is clipped, but I blew air through it, on the intake side, front of Venturi, air passed through it to the back side, EGR side of the DP sensor. Should that not be closed, so that air cannot get through the sensor? Or does it close when power is applied?

I sealed the holes in the DPS, its not functioning so what the heck. Used the red RTV and put her back together. Found the heat Shiel on the EGR valve rotted away, so I ordered a new one, not much left of it. EGR valve body looks good. See no need in taking that off.

Sounds like the sensor went bad.

- (de-mandated engine only) Some guys will fill the DP sensor cross-pipes with red silicone to prevent any bleed-through or pressure getting to the disabled sensor.

-- Maybe take an oil sample and send it to a decent lab. See what soot and other levels are.

[Waterloo]

Thank's Rawze, I poked around, did the overhead, fixed that front cover leak, new AC compressor and am still perplexed about the oil. When I found I could blow through that sensor, I figured that has to be it, only thing I can figure as everything else looks good.

The YTS turbo is spotless and slobber free. No oil anywhere, unlike the two previous cummins reman turbos at double the cost.

We shall see what happens, I just had the truck serviced so time will tell. I'll get that oil sample, will order a cup online and send it in, see what the results are. Any recommendations?

[Brock]

Yours is a bigger cpl engine isnt it? A factory 525? Is the programming set conservatively with the timing for a higher cpl engine? Even though your hp is set lower.....

Any chance this is your issue? A demandated isx wont necessarily clean up the oil without pushing the timing?

[Rawze]

(10-08-2019 )Brock Wrote:  Yours is a bigger cpl engine isnt it? A factory 525? Is the programming set conservatively with the timing for a higher cpl engine? Even though your hp is set lower.....

Any chance this is your issue? A demandated isx wont necessarily clean up the oil without pushing the timing?

its a delicate balancing act. Always reliability and longevity vs. higher efficiency. They contradict each other.

There is such a thing as "too clean" of oil in an engine.
There is also such a thing as "Too efficient" for any given HP and torque too.

push those boundaries too far and a severely shortened engine life will result. Seen a lot of guys try to make a 1850 or 2050 engine (500+ hp and up) push high timing advance, trying to cheat that extra bit of fuel mileage, only to end up with a fretted liner or cracked piston.


Mine used to have clean lt-brown coloured oil for 20k+ miles at a time for it being set at 435HP, 1650 trq most of its first million miles. - was not so good for the components, but I got away with it for 950k miles because torque was low and I did not drive it hard.

It has since been re-programmed to where the oil starts to get a bit dark at about 10-15k miles or so, seems to be the optimum for me anyways, and 20k you can barely see the stick under it (though I don't let it go that long very often). Power is now set to 1720ft-lbs/ 450hp though too, so I had to back it off the efficiency a bit to keep it safe.

Waterloo's truck is a big tier engine. Bigger bowl piston, bigger injectors made for larger fuel flow and different angle, different cam for more air flow .. all add up to lower compression and a bit less fuel burn efficiency. Combine that with bigger turbo vs mine as well, and that is less efficient overall too. - Still, it is impressive what fuel mileage he is squeezing out of that thing because he is driving it right and HP/torque is turned down. it is not surprising that his oil does not stay quite as clean as a mid-tiere truck will.

It can most likely be tuned so that oil runs slightly cleaner, but at what cost to the components?. - he is getting good fuel mileage out of it,.. best leave it in its safe zone, especially him having a rocky history with it in its past. Last thing someone needs is more problems simply because they want to see the oil a bit cleaner, or those last few tenths fuel mileage.

[Waterloo]

Good to know, when I had the original @m*m^2 the oil stayed nice and honey brown up until 10,000 or so miles with 450 or 485 hp setting and torque at what 1700 or there about. It was nice to see that clean oil, but if running a little dirty will keep things going, I'll take a little dirty. The truck is running incredibly well, knock on wood. Fuel mileage is well over 7 mpg dragging around a dry van with my mid roof, moose slayer bumper along with all of my other nonsense on the truck. I just weighed the tractor with full tanks, 22,350 lbs, she is heavy.

That Tri-Pac of mine is the fuel pig in this equation. This new Evolution unit is sucking a gallon+ an hour, you can watch the fuel gauge on the dash move, seriously. I miss my old Tri-Pac that used half the fuel, I may as well just idle the truck, because I am not seeing any fuel savings. Need to take it in soon for its yearly service, I'll have them see if something is amiss when they hook it up to their diagnostics software.

Then the motor, I really dug into her this past week, it looked good in there, front gear train, valve train and on both the exhaust and intake side. The differential pressure switch was the only real surprise, hopefully the RTV will fix that.

When I was out west, I ran her hard when in the mountains, gave the motor a workout. First time she has seen those in years vs the flat land. The truck performed nicely, kept boost low, RPM above 1500, never touched the cruise control, Jakes were very strong, first time I have turned them on in a long time, like years. I was almost afraid to use them, LOL! Temps were all running within range, nothing weird there, truck ran incredibly well and still is. Those 3:42 gears have to go, just a total dog, I'm thinking 3:70.

Hopefully we will be back to work this week, these contractors are costing me money, I'm finding them to be the same as the local dealership, use at your own peril. You should have seen what I saw yesterday, Larry holding an 8 foot long 1" x 8" at the end, Curly on the tiny contractor table saw using the fence to crosscut a 1" wide piece off the other end of the board. I about had a stroke when I saw that. All I could see was the ambulance coming up the drive. I yelled at them to stop before one of them lost a limb. I picked up my BIG tri-square, within a few feet of both of them, and reminded him that he can use that as a straight edge/fence with his circular saw. Oh yeah! My God...

[DDlighttruck]

I’m confused. My oil is black, soon after every oil change. That’s not normal? I did forget to sample it last time, I need to sample it here shortly