"Normal" Oil Usage by Diesels?

[Kings Gambit]

Is it normal for diesel engines to consume engine oil, and if so, at what rate(s)? What would be considered excessive or "beyond normal" usages? If running @ 3000 RPM for, say, 7 h, how much, if any, oil might a 39-hp, 3 cylinder diesel with nearly 2000 h consume "normally?" Does higher wt oil mitigate consumption?

 

[LeslieTroyer]

I put about 50+ hours on mine this season - maybe lost 2/10 quart. Don't know how many hours it has on it but quite a few.

Les

 

[Rich Stidger]

I see about a quart usage for 130 hours during a season in my Volvo MD22L-B (2300 hr). In my 5kw Westerbeke generator (2600 hr) for the same 130 hours of running I see no oil usage. I use straight 30W Rotella diesel oil in both engines.

 

[centerline]

A diesel engine doesnt use anymore oil than a gas engine would...
the particular engine in question may be an oil burner, but dont assume all engines that run on that fuel are the same...

As for the oil.consumption, some engines are installed at an angle and depending on how it has been engineered, or if someone changed the dipstick, the crankcase could be holding more oil than it should, in which case it will burn the excess off at a noticably high rate, even though nothing is wrong... not always burning it as we think an "oil burner" would, but it could be being spashed ip towards the crankcase breather tube and being sucked into the intake, and being burnt as it passes thru...

Make sure you are putting in the correct volume of oil for the engine in that particular install arraingment.. than you can see if it continues to use oil...

 

[centerline]

Is it normal for diesel engines to consume engine oil, and if so, at what rate(s)? What would be considered excessive or "beyond normal" usages? If running @ 3000 RPM for, say, 7 h, how much, if any, oil might a 39-hp, 3 cylinder diesel with nearly 2000 h consume "normally?" Does higher wt oil mitigate consumption?

It shouldnt be using much oil at all... but we dont know.how its been ran most of its 2000hr life.... a diesel running at low rpms and puttering around all the time can carbon up just like an older gas engine... the rings could get sticky and cause a higher rate of oil consumption, but its not likely the engine is wore out or needs a rebuild... unless it cant be cleaned up with additives.
And again, seafoam is your friend here. Used in the crank case and in the fuel, it will dissolve any carbon build up and allow the parts to work as they should... its not a miracle cure, but its just cleaning any old deposits out from where thy shouldnt be.

Sticky piston rings dont seal against the cylinder wall like they need to and so its possible to lose compression as well as let oil up into the combustion chamber, which otherwise would be wiped back down into the crankcase.

 

[Justin_NSA]

I had a diesel Benz that I put a lot of miles on. It didn't use oil but it sure made it look filthy.

"A diesel loves his oil like a sailor loves his rum" Captain Ron

 

[Stu Jackson]

KG, we did 165+ engine hours on our trip from SF to BC last summer. I had to add 1/2 of one CUP in that entire time. M25 three cylinder Universal (Kubota) diesel 21 hp, 3,200 engine hours when we arrived.

In the past 18 years, I do oil changes, never had to add any between changes.

 

[Rick D]

About a quart in 120 hours on our 4jh Yanmar with 2800 hours. That's a lot of running at 2800 RPM for long periods.
Rick D.

 

[Gunni]

Yanmar 4JH3E (2 ltr., 4 cyl.) - 800hrs, 150 hrs, per season. Never added oil in 6 years of ownership. Checked the OEM SS exhaust elbow last year and it had a thin coat of black. Rotella 15W-40. Same with the Kubota 2cyl. Genset engine. Both run cool.

 

[Justin_NSA]

Yanmar 4JH3E (2 ltr., 4 cyl.) - 800hrs, 150 hrs, per season. Never added oil in 6 years of ownership. Checked the OEM SS exhaust elbow last year and it had a thin coat of black. Rotella 15W-40. Same with the Kubota 2cyl. Genset engine. Both run cool.

Gunni, you have a SS exhaust elbow? I am replacing mine and wondering if it's a good upgrade from cast iron.

 

[Terry Cox]

Average about 100 hours per season between oil changes on our 1991 4JH2-TE that has 1,900 hours total and have never had to add oil. Ditto our Onan Genset with a three cylinder Kubota engine that has 450 hours total, but usually run it less than 30 hours each season.

 

[Maine Sail]

Westerbeke 44B Four (Mitsubishi S4L2) 1000+ hours (lots of that for charging and engine driven refrigeration) absolutely no measurable oil consumption at all and no transom staining. Engine has been religiously run with Rotella 15W-40...

 

[Benny17441]

Agree, no more than a gasoline engine of similar hours would use. Yes, utilizing a higher weight oil will reduce the amount of oil that may seep through the rings from the crankcase to the combustion chamber. It will also increase compression and require less starter cranking revolutions at start up. The downside is that the heavier oil will thicken at cold temperatures making it harder for the starter to turn the engine. It will also cause a minimal increase in fuel consumption. In a 2000 hour diesel marine engine I would use a premium 15W40 oil. Diesel engines run more efficiently and cleaner when hot so avoid extensive idling which leads to carbon build up.

 

[Gunni]

Gunni, you have a SS exhaust elbow? I am replacing mine and wondering if it's a good upgrade from cast iron.

My Yanmar 4JH3E came OEM with the stainless steel mixing elbow so it never occurred to me that there was a problem with any of the elbows until the folks with cast iron elbows started talking about problems. They say that the elbow should be replaced at 500 hours but I saw no sign of blockage or corrosion at 650 hrs . I do know that the fellas at Mack Boring are very adamant about not idling the Yanmar for extended periods - exhaust deposits.

 

[Charles Erwin]

I would venture that a pretty high percentage of cases where oil consumption is deemed excessive are attributable to failed valve stem seals and/or excessive valve guide clearances - not rings or piston bore condition.

Charles

 

[Mark Maulden]

Couple oz in about 150 hrs using Delo 400 30wt. Used even less when I used Delo 100 but can't get it anymore. I did rings/valves several yrs ago. (36 yr old Volvo MD17C) Ran it maybe an hr at the dock and made several trips out to break it in which was widely varied speeds and even throttle slams in both directions..the first season was paying attention to varying the speeds...i think most boat engines are not broke in well as they are used either to either "clear the breakwater" or clear it and keep it at one speed and go early in life..

 

[Kings Gambit]

Thanks for all of the input. I'll investigate the ideas about possible reasons for oil consumption by my 3JH3E. It seems excessive, lately, by the comparisons. I've added nearly a liter of Delco 400 15W-40 over the last 40 h of operation, probably 40% of that charging at anchor or idling. Valve clearances were adjusted lately and the injectors chemically cleaned at the same time. The SS elbow is the original and has not been inspected for probably 1000 h, so I'll look at that next. I do fill it to the top dipstick line and maybe that's not the correct volume to keep in there; however, have not noticed such consumption in the past.

 

[Justin_NSA]

Have you done a compression test? Rings could be stuck. The other common possibility as mentioned are the guides and seals. I've not had much experience with marine diesels, but I can see where excessive idling could cause carbon buildup. I've seen immediate results using Seafoam. Others can chime in on this suggestion.
https://seafoamsales.com/marine/

 

[alexco38]

Over filling oil is actually bad. Oil got splashed around especially with a bit of heel. Remember when you fill, the oil is cold. When hot the volume expands. I had low oil pressure alarm one time when the oil level was filled to the top mark and we motored for an hour to get away from a storm. Now I only fill to the middle between the 2 marks. BTW my Volvo2002 has about 2000+ hours. No oil lost yet.

 

[Kings Gambit]

Have you done a compression test?
https://seafoamsales.com/marine/

A type of one I suppose; my mechanic told me when he did the injector cleaning that serial "removal" of injector function caused the engine to respond appropriately (spot on) working on the remaining two cylinders, etc. Not that familiar with mechanics' techniques for testing engine status. Does that count as some kind of short cut to a compression check?