losing motor oil!!!

if the motor has that many mniles without an overhaul. it could be oil slipping past the piston rings. into the combustion chamber and out the exhaust.

it may also be coming from the valves.

if you can, watch your exhaust. see if you get grey smoke with heavy pedal. or with no pedal. like jake brake.
heavy pedal means it's sucking up past the rings. no pedal means it's oil beig sucked through the valves. or jets or whatever.

you didn't post what year truck you got. so others can offer more helpful answers. like is it an egr motor or dpf by chance. or an older motor.

according to a late night radio show. usually when you can't find leaks or answers to your oil consumption. it's becuase the motor itself is burning oil. inside.

 

Agree with snowwy on this. That much oil and no visible leaks I would say it is burning it up. Rings on pistons. Time for an inframe.

I had a guy that was burning up mega amounts of oil each week. He came into the shop and I was going to pull it around back to pressure wash the engine. (14 L Detroit in a Freightliner Classic) He had some leaks but nothing that was for the amount of consumption he had. When I got into the truck I noticed his meter for his air filters was maxed out. So I reset it. Pulled the truck to the rear of shop and it was maxed out again. Well that is not good. Took his filter housing cover off and found filthy filter that had actually started sucking apart. Called the customer and told him what the deal was. Poor maintenance let to dirt in engine which got his rings. He told me he had just changed his air filters. Well there was a date on the filter. 2004. The truck had the original filters in it. This was 2010. Pulled the engine down and he actually had a ring missing...

 

I hate to say but it is probably wore out needs a rebuild mine did this all cylinders were shot and polished like chrome from all the egr soot ! Mine had 402000 on it when mine went south im surprised that it made it that long after I realized how much soot goes back into it! No wonder a egr engine don't last !!

 

I have a lot of pto time for what I do as I was loading mine would soak the flex pipe off the turbo while driving it would get hot enough to burn it off and at nite under lights would have a slight smoke haze out the exhaust. If you do a overhaul make sure that who ever does it does it right !! Mine was done under warranty 134000 miles ago and it blew a head gasket and now come to find they didn't clean the counter bores out properly and now I need the block cut and inserts installed so just make sure that you use a reputable shop for the work good luck!!

 

How long do you go on PMs and does it burn 3 gallons of oil right after a PM? If its not leaking it there aren't many other places for it to go.
Do you do much fast or slow idling?
Add some Lucas and see if that helps but most likely it will be expensive.

 

Do not add Lucas.
Cummins makes an oil dye PN 3376891, add it to the oil, and run it at 1500 RPM for 15 minutes when it is already hot after a trip, or add it and then drive it for half an hour, then remove the turbo outlet, and look for oil, a black light works best but just a flash light works, if the turbo is wet remove it and if the exhaust is OK then it is the turbo, if the exhaust is wet then remove that and look at the exhaust port, if many are wet then it needs to come apart.
The turbo you need a cover for the inlet, and presurise it to 10lbs if it is bypassing air to the crank case it could be blowing it out the vent when driving. Preasurise the intake of the engine, if you get a lot of air out the vent the valve guides are worn.

 

There are a few things it could be. But with that many miles most likely it's time for linears, pistons and rings. JohnP3 is right, I mean it's a possibility, but with those miles and no oil leaking onto the ground it's safe to say it's slipping by the rings and coming out the stacks.