How often do you change your oil

How often do you guys change the oil in your engines? Time based or engine hours?

100 hrs or end of season, whichever comes first. Same with tranny.

Depends on usage. Normal Summer season in Northeast means 100-150 hours. I change Cummins 6BTA5.9 engine and Twin Disc transmission oil before winter lay-up. Cummins handbook states every 250 hours but last year Cummins Technician said 350 hours was OK before we took off on our Bahamas Winter cruise that put 650 hours on the boat. Engine hardly burns any oil at all!!
Chris

Every 200 hours on our Ford Lehman SP135 with 7386 hours.

Chrisjs,
You better hope it does burn some oil. There is a ring on the piston that's called an oil control ring and it controls how much oil is left on the cylinder walls when the piston comes down. With an engine in good condition the oil control rings provide enough oil on the cylinder walls to lubricate the cyl walls, the piston and the upper compression rings. Burn no oil = lots of wear.

I use an engine bypass filter (Gulf Coast), on my Cummins 5.9. Every 100 hours I replace the filter and top up with about a gallon of Delo.

Every 500 hours I replace all the oil and regular engine filter too, as a matter of course - even though they say I don't need to.

Oil analysis once a year.

FL120 manual says to change the oil and filter every 200 hours. We change ours every 100-125 hours. And of course the injection pump's lube oil is changed every 50 hours.

Once a year

Even though I use block heaters though out the winter and early spring months I change my oil each year. It would be unlikely for the average boater to exceed 300 hours a year so I'm well with in my recommended change interval. Even in the temperate central valley I feel block heaters maintain a dry engine and engine room extending the life of everything in the engine room. I probably could extend oil changes out for two - three years or so. My Detroits are 36 years old still running original heat exchangers , oil coolers and starters. The engine start instantly so I believe the starter life is extended as well by the use of block heaters. I don't read much about the value of extending engine life with block heaters but my experience has been very positive.

Really depends on the Use.

On the Loop or ICW transit 125hours is norm.

Just putzing about once in awhile 50hours.

DD factory bypass filter ,no full flow fitted ,engine is too old.

FF

In my Lehman, any where between 100 and 200 hours, depending on the season ans use.
When I had my Cummins 6BTA, it was 300 hours some years (the manual said 300 hours). And it didn't burn enough oil to measure or think about uless I was really hammering it.

I went back to my log book for more precise info on oil burn. When I first got my boat it had 1130 hours on the Cummins 6BTA5.9 /280HP. We motored non-stop (24 hours a day) for about a week from Lauderdale to Rhode Island. We covered about 1,200 nm, burned 450 gal of diesel and used 1 gal of engine oil (Rotella 15/40). The engine now has 2,500 hours and still does not burn much oil, even when we do 24-30 hour overnight runs. I had an Audi A6 that used to suck down about a qt. every 1,000 miles. Dealer (liar!!)said it would get better with time - never did. On the other hand my old Jeep Grand Cherokee had 140K miles on it when I sold it last month and never needed any oil between 7,500 mile services. I think the story about "good" engines needing to burn oil is just that --- a story promoted by poor engine builders!!

Chrisjs said:

I had an Audi A6 that used to suck down about a qt. every 1,000 miles. Dealer (liar!!)said it would get better with time - never did. On the other hand my old Jeep Grand Cherokee had 140K miles on it when I sold it last month and never needed any oil between 7,500 mile services.

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Audi/VW engines are well known to use oil throughout their life.
My FL120s rarely need topping up between changes,usually performed around 100hrs or annually. I understand that apart from becoming contaminated by usage over time, oil qualities deteriorate with oil age too,thus the advice from auto manufacturers to change oil by time as well as miles, which if true,has to apply to boat engines too. BruceK

manyboats said:

Chrisjs,
You better hope it does burn some oil. There is a ring on the piston that's called an oil control ring and it controls how much oil is left on the cylinder walls when the piston comes down. With an engine in good condition the oil control rings provide enough oil on the cylinder walls to lubricate the cyl walls, the piston and the upper compression rings. Burn no oil = lots of wear.

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Guess it depends on the definition of "some oil". My dodge pickup has the same Cummins 6BT-5.9 engine that my boat use to have. The oil barely moves on the stick between oil changes (every 5,000 miles). With 305,000 miles (6,000 +/- hours) there doesn't seem to be any wear on the engine for not using any appreciable amount of oil.

Now my charter boat engine, Cummins 6CT-8.3 (300 hp) gets an oil change every 50 hours. But then it's burning 10 to 14 gallons per hour as compared to my pick up which burns 2.5 to 3.5 gallons per hour.

Ted

Engines,will,use,oil,as,some,must,be,left,on.the,cylinder,walls,to,prevent,seizing.

An,engine,that,"does,not,use,oil"is,simply,accumulating,blowby,and,gunk,at,about,the,rate,the,oi,is,being,used.

That.is,why,there,is,the,change,requirement.

100 hours or annually, whichever comes first per Bob Smith. He did say that if you're using the engine hard, like full time cruising, you can go 200 hours.

"Not using any oil" can be the same as "the volume of oil consumed is replaced by diesel fuel and air products." What is this stuff? Well it can be one or all of the following:

• tar/asphaltines
• sulfates
• antifreeze
• diesel fuel
• water
• other products of combustion

All of the above plus some get washed of the cylinder walls by the oil and drop by gravity back into the pan. If your oil temps do not get above 180 F or so many of these contaminants will linger and build up, possibly raising your oil level. If you don't do routine oil analysis, following the book change out hours is a good idea.

That's super interesting Tom. I did'nt know the volume of oil actually increased from these contaminants. But fuel in the oil certainly has volume. And I did wonder how an engine survived not burning any oil at all as it would seem there would'nt be any oil on the cylinder walls at all. Since I've always thought these contaminants were only present in "trace" amounts now I wonder how much there actually is.

I change my oil at least 3 or 4 times a year. I frequently change the oil in the engine and not the filter. It promotes me to change more often that way and I get most of the carbon out of the oil. I just changed it last week (and the filter) and I'll change it once during our trip south. With'in reason I do'nt think one can change oil too often and if you change oil in the fall and do'nt use your boat in the winter you do need to change it in the spring. It's my opinion that one needs to change synthetic oil as often as dino oil in a diesel as the worst contaminant is carbon and it should accumulate as fast w syn oil as dino.

Surely, contaminants such as this would show up in an oil analysis. last time we did one, ours was fine.
Chris

manyboats said:

With'in reason I do'nt think one can change oil too often and if you change oil in the fall and do'nt use your boat in the winter you do need to change it in the spring.

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What's the benefit in changing 6 month old unused oil?

For oil consumption in a decent running 4 stroke diesel, a term that is used is FSOC or fuel specific oil consumption. This number normally is 0.075 to 0.15%. New tight Tier II engines may be as low as 0.05%. At 0.1%, for every 1000 gallons of fuel, 1 gallon of oil will be used. Another rule of thumb is 0.15g/kWH or about 10 grams of oil burned per hour in an engine operating at 100 hp. Rules of thumb are just that, but some oil indeed gets burned in a diesel operating normally. This summer I plan on using about 2000 gallons of fuel so every few weeks a quart or two of Delo 400 15-40wt will be needed.

If one only racks up about 50 hour per year on their engine, it is easy to see how "it doesn't burn any oil." DD 2 strokes burn much more, not a negative, just how it is.

Can't remember what the details are and it seems silly but I've heard and read for decades that oil degrades while sitting in an engine. I'm quite sure condensation plays a part. I'm not on BoatDiesel anymore so I can't ask and I was hoping Tom would answer that question. I've heard it so many times I don't think it could be a debatable issue. Hopefully someone w the details will surface.

Eric: For the best information go to Chevron and/or Shell's websites. My two cents worth based upon 40+ years of running and maintaining all manners of big iron follows:

If you change oil by the book you can't go wrong. Most people change oil in the fall just before a winter layup then assume it is OK for the next season, Some more dedicated change it in the spring and fall, the old 6 month rule, to deal with moisture which does indeed accumulate in the engine's innards during the winter layup.

And yes just sitting and oxidizing,oil can begin to wear out, but I doubt in 6 months given today's oil additives, whether dino or syn. BUT in many boat engines the last quart or 3 won't easily come out, so you never have 100% clean oil sitting there during the winter. Me, since I run my engines to temperature at least every 5 weeks during the milder winter in Victoria as compared to Thorne Bay, I change oil by the book hour (400 in my case) or annually, whichever comes first.

If you own a fancy car where the builder provides free service for XX years, they change oil based upon the onboard computer, sometimes as much as 8,000 - 10,000 miles. In the book the same car says 5,000 miles or less. It sometimes depends on who is paying.

"It sometimes depends on who is paying."

True , but I have never heard of an engineer or wrench telling an operator ,

DAMN. "You changed the oil so often the engine is shot!"

Oil is cheap, when in doubt , change it out!.

FF

Simple... Every year. Usually in the spring.

Tom-

I change the oil in our Detroit 8.2's every 100 hr; change the oil filters every 200 hrs, & do an oil sample at least once a year. Engines don't show oil use until I get near the 100 hr point; then they will use a little bit. Trans. oil (Twin Disc) gets changed @ 150 hrs.

100 hours or once a year, whichever comes first. We use the boat year round.

GonzoF1 said:

Simple... Every year. Usually in the spring.

Tom-

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We in the frozen NE usually do it in the fall when we haul for the season on the theory that we don't want the contaminants in the old oil to sit in the engine all winter.

dwhatty said:

We in the frozen NE usually do it in the fall when we haul for the season on the theory that we don't want the contaminants in the old oil to sit in the engine all winter.

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In NC, we boat nearly, if not actually, year-round, but I have heard that too.

My engines are rated for 400 hour changes. I change in the late fall, but run to operating temperature every 2-3 weeks in the winter and keep a heater on in the engine room which keeps things dry and cozy. I might go on a few day trips in the winter as well.

manyboats said:

That's super interesting Tom. I did'nt know the volume of oil actually increased from these contaminants. But fuel in the oil certainly has volume. And I did wonder how an engine survived not burning any oil at all as it would seem there would'nt be any oil on the cylinder walls at all. Since I've always thought these contaminants were only present in "trace" amounts now I wonder how much there actually is.

I change my oil at least 3 or 4 times a year. I frequently change the oil in the engine and not the filter. It promotes me to change more often that way and I get most of the carbon out of the oil. I just changed it last week (and the filter) and I'll change it once during our trip south. With'in reason I do'nt think one can change oil too often and if you change oil in the fall and do'nt use your boat in the winter you do need to change it in the spring. It's my opinion that one needs to change synthetic oil as often as dino oil in a diesel as the worst contaminant is carbon and it should accumulate as fast w syn oil as dino.

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If I may make a suggestion, you are better off changing the filter more frequently. You can actually skip changing the oil, but I don't recommend skipping on changing the filter. The filter has a capacity that it can hold. Once that is reached, it can no longer catch the impurities. I also recommend attaching a 5-10 pound magnet to the filter side. I do this on all the filters of all of my vehicles. Then, when I change the filter, I cut it open and see what is there. If there is metal it can tell me what is going on inside the engine. Paper filters do not catch organic compounds commonly found in oil and diesel fuel, but they do catch other things like metal. They do make filters that will catch organics, but they are pretty expensive. Oil will last much longer than most will let on, especially if the engine is run at the designed RPM and load ranges more frequently than not. Our Volvo's have just over 15,000 hours, never overhauled and run just fine. I agree with the block heaters. Every commercial ship I have been on has had them running at 150-165 degrees F whenever the engines are not running and we do the same with ours, although on our boat the heaters are elements and not steam operated. Just a few thoughts. I hope they help.