[Glenn and Laureen]

Gurus,

For those who drive a Classic with a Detroit Diesel 6v92 or 8v92 series engine, what level of oil consumption do you experience? A quart every 1,000 miles? 2,000 miles, hardly any? Also, I assume everyone uses a 40wt oil, either Chevron Delo 100 or Shell Rotella. I have a 1984 6v92t engine and seem to have added about 2 gallons (8 quarts over the past 9-10,000 miles).  Did some heavy mountain driving out west, going over several 10-11,000 foot passes in Colorado. (Engine ran like a champ the entire time.)

(Delo 100 was put it at last oil change. Have another oil change coming up next week.)

So, is my usage in the ballpark or should I be concerned?

[folivier]

Did this just change? There is an issue on lots of diesel engines where the dipstick is not marked correctly. This has to do with what oil pan your engine has. If the full mark is actually overfilled the engine will throw out the excess until it reaches the normal fill level. Just putting this out there to look at before you make any assumptions about your engine.

[Glenn and Laureen]

We have owned the coach for only 2 years so I don't have much history of oil use or appropriate marks on the dipstick.

[ccjohnson]

I average 3-6 qts over 5-7.5K miles

[whatsnewell]

Glenn, my 6v92 uses a quart every 14-15 hours of operation. At 60 miles per hour that's about 900 miles. So, it would seem you are doing fine. 2 strokes use oil....it is normal.

[Fulltiming]

I find that if I fill my oil level to the full mark on the dipstick, I use more oil than if I fill it to 1 quart below full. I check my oil level each day when traveling and if it gets down about 2 quarts, I add a quart. You are in the right oil consumption range for an engine with usage. I also find that if my coach sits for an extended period it uses oil at a somewhat faster rate than when it is being driven long mileages on consecutive days.

I do use Delo 1000

[Glenn and Laureen]

Clarke, thanks for the comment. Looks like around 1 quart per thousand miles is doing OK.

Thanks to CC and Forest for their replies also. Forest, my engine was throwing quite a lot of oil around for awhile. Perhaps I did put a little too much oil in to top it off. Or perhaps the previous owner really cleaned up the engine bay before I bought it.

---

Michael Day I think I will adopt your strategy and leave it a little short of my full mark.

[Tf175]

I run the 8V92 about 2/3 the way between add and full . Michael advised me against filling to full mark when we first got the coach  . We haven't made a lot of trips , but a quart or so in 1k miles is about right. I use Mobil Delvac 1240 , 40 wt. Low ash ,made for DD two strokes . Summit has it so it's convenient for me. 
Chris

[folivier]

Our first trip in our '93 with 8v92 I was towing a silver Miata. When I got to Creede it was covered in oil. I had an oil change just before the trip and they filled it to the full mark which was too much. After that the oil consumption was very little, only a couple quarts between oil changes.
It's worth the time to determine your proper oil level and mark your dipstick. And make certain whoever is doing the oil change knows which mark to use.

[Richard]

I was watching a program that concerned building high performance race engines. Part of the program showed them trying different tricks on the same engine, and putting the engine on the dyno each time.

This episode was testing different oils and different oil levels with regard to horsepower. That’s not material to the conversation except oil levels at full in this test produced less horsepower and LESS oil pressure. Seems the crank whipping around a few thousand times a minute will beat the oil into a froth if the oil level is too high. Of course that robs power, but what is relative to this conversation is the other thing that happens. It beats air into the oil, and forms an oil aerosol in the crankcase. In our case, that aerosol makes it’s way to the slobber tubes.

I see the same thing on my Series 60. Until @rheavn told me 36 quarts, not 40, I was adding an extra gallon each oil change. And seeing the front of my toad rustproofed each trip. As soon as I started with 36 qts., the toad oiling ceased. At 40qts the oil level was just barely over the full mark so the dipstick was no help in figuring out how much oil the engine actually wanted.