Engine/Transmission (1994 - 1998) Do high mileage Cummins use oil?

[GAmes]

I remember reading on this forum that turbo-diesels won't burn oil like gassers because the intake turbo boost pressure keeps the cylinders full of air on the intake stroke unlike a gasser that relys on suction pulling the air/fuel mix into the cylinder and pulling oil in at the same time. Any truth to that? I have chased oil leaks it seems like forever and have replaced every gasket and seal in the exterior of the engine at least once. I recently replaced the vac pump/PS pump seal again and now the only trace of oil on the outside of the engine is a very small drip from the rear of the injection pump. The engine has used 1 1/2 quarts of oil in the last 2100 miles, but that little drip is not a 1 1/2 quart leak. If it makes a difference, most of that 2100 miles was driving on flat ground (south TX) unloaded (which would be low boost), about 60 miles was pulling a 3000 pound boat. Can I just be comfortable in the knowledge that high mileage engines use oil or do I have a problem?

 

[hsmith]

Hey Gary,
If my truck runs as long as yours, mine now at just 200k and using no oil at 5k o/c intervals, I would be pleased to not have to add more than you.

BTW, is it still the good looking truck I remember? I had to have the Driftwood on mine redone as the clear coat was peeling real bad.

Smitty

 

[FourBarR]

My truck just passed 500. 000kms( 300,000k) does not use any oil between changes at 10,000kms (6000k) Used Rotella 15/40 since new. Hope this help.

 

[Bob4x4]

All engines use oil... ... ... ... . if they did not the valves would cease to go up and down and the cylinders would be scored till they locked up. The only question is how much over what period of time. The Dodge acceptable spec is something like 1 qt per 1k miles. Since the safe zone on the dipstick is somewhere around 2 qts we have a bit of leeway before we think we are using too much or admit to using any

 

[GCordrey]

Gary- Just curious, have you had any turbo work done? I've seen where the bronze/brass/whatever sleeve or bearing has worn, and was letting the turbo oil into the cold section of the turbo. This oil would end up in the induction system, then burnt in the cylinders.



What I described happens in General Aviation turbocharged engines, not sure the same theory would apply here.

 

[fest3er]

... The engine has used 1 1/2 quarts of oil in the last 2100 miles, but that little drip is not a 1 1/2 quart leak. ...

Some high mileage engines use oil. Mine did, until I vented the crankcase (replaced the oil filler cap with some PVC plumbing). Oil usage dropped from a quart every 500-1000 miles to a quart every 5000 miles.



As it was explained to me, the crankcase is vented to allow blow-by to escape. If there is excessive blow-by, the small tube can't vent it all, and oil from the top of the engine can only drain so far back down before it finds other ways to leave.



If there's blow-by, it's possible that the rings are not removing enough oil from the cylinder wall, and the engine is burning some of this excess oil. Also, oil may be ejected as vapor and/or mist.

 

[RyanStewart]

I used to drive 18 wheelers, most of them Cummins M11 and N14 powered. The company didn't take very good care of the trucks and most of them used oil, some as much as a gallon in less than a week (usually about 2k - 3k miles worth of driving). I've heard the same thing, that because the cylinder is always under positive pressure Diesels don't burn oil, but that hasn't been my experience. Some of the trucks I drove leaked, but there was never enough under the truck to account for a gallon lost in less than a week.



BTW I have a 6. 2 Diesel powered K5 Blazer that I drove until a couple years ago. When I parked it at 280k miles it was using a quart every 700 miles but it wasn't leaking a drop. That oil had to be going somewhere.

 

[surfbeetle]

Don't forget to check the internal oil cooler. You could have oil leaking into the coolant. There's also the rear main seal. Good luck.

 

[HBarlow]

Gary,

IIRC my old '01 was consuming a little less than one quart between 10,000 mile oil changes when I retired it @ 325k miles.

 

[GAmes]

Smitty, from a distance it looks OK, but a closer look will find the paint worn on the fender (guess I should have used a cover while changing fuel filters), numerous chips and deteriorating paint on the roof. GCordrey, never touched the turbo, but I'm sure that isn't the source for two reasons. 1, I pull the intake tube from the intercooler to access the PS/VP for removal. The tube was dry 2100 miles ago. 2, oil into the inlet will probably result in a runaway engine. fest3er, I have a bottle attached to the blow-by tube, it has very little oil in it. surfbeetle, no oil in the coolant and the rear main seal was replaced not too long ago. Zero oil on the bellhousing. Harvey, this just started in the last 150k or so, I think. As you know I fix one leak after another, but since the miles I drive has drastically been reduced the miles between fixes has also been reduced, so for a change all the seals and gaskets are low mileage Thanks for the responses so far, it looks like oil usage may be normal.

 

[surfbeetle]

Just a quick unrelated question, you said a bottle on the blow by tube, what did you use? Wife is sick of the oil leaks on the driveway, I'd like to prevent that if at all possible.

Thanks

 

[Dieselnut59]

BTW I have a 6. 2 Diesel powered K5 Blazer that I drove until a couple years ago. When I parked it at 280k miles it was using a quart every 700 miles but it wasn't leaking a drop. That oil had to be going somewhere.

Remember, the theory mentioned here is turbocharged diesel engines. The 6. 2 would "suck" the oil by, much like a gasser, except for they do not have "vacuum" under a throttle plate, only the restriction from the air cleaner, hose and intake manifold. The turbocharged one would always have somewhat of a positive pressure. If my engine/truck lasts to 650,000+ miles, I would gladly add the amount of oil you mentioned. I pour the old crankcase oil in the fuel tank on my '96, so it really wouldn't be that much different! :-laf

 

[GAmes]

Just a quick unrelated question, you said a bottle on the blow by tube, what did you use? Wife is sick of the oil leaks on the driveway, I'd like to prevent that if at all possible.

Thanks

I used a 16 oz Skippy peanut butter jar, they are made of light plastic.

Any lightweight plastic jar will work. I drilled a 1 inch hole in the lid with a wood drill bit, and 4, 1/4 inch holes around it for vents. I slid the lid up the hose and put a zip tie below that to hold the jar up. Screw on the jar and dump every other oil change or after an engine wash (the little holes allow water to get in).

 

[JHastings]

With 650K on the clock, I would guess that your oil consumption is OK. I use oil with only 140K on the clock and no external drips or leaky turbo with an extra breather.

 

[surfbeetle]

GAmes, thanks for the bottle tip. Now as for the oil loss, another possibility is you're just burning it, what color is your exhaust? A bluish white can be more oil getting past the rings. But then again, we all seem to agree that boost pressure should be mitigating that to some extent.

 

[GAmes]

I'll pay more attention to the exhaust color. The only time I look in the mirror specifacally for smoke is when I am trying to fill a ricers window with it. :-laf

 

[Mhannink]

all engines use oil, and before anyone says anything i know most of you dont see it. the truth is thought that every engine burns oil. i know for cat and im sure cummins has it too there is a brake specific oil consuption rate for every engine. the amount your using though i wouldnt worry about it especilly for the milage

 

[Bob4x4]

See post # 4

 

[CumminsPower98]

My truck had 67k on it when I got it. From that time until 122k running on Amsoil 5w30 HDD it used about 1 qt/6k miles as a daily driver unloaded empty. When I started transporting RVs it started using more like 1 qt/3k miles and stayed pretty steady at that rate up to the present with 402k miles. My feeling is that running higher speeds combined with extended high boost causes more oil consumption. I have a breather tank system to catch the oil and I don't get huge amounts out of that but enough to make a mess if it wasn't there. I never did calculate how much I collected for a set mileage figure. I am no longer driving OTR and the truck is sitting most of the time so I don't know what it would do as a daily driver now. It would have been interesting to have installed a second breather when I was out driving to see if that changed the consumption rate at all.



I agree that all engines use some oil in order to keep things lubricated as was already stated.

 

[GAmes]

Then I'll keep adding oil and wait for the next leak. Getting the truck and 5er ready for a trip to Alaska. Is there a limit on how much oil I can carry into Canada?:-laf