Oil change interval

[Don L]

I agree. I believe it is engine hours and time dependent. If you are like Peter and running regularly I'd extend the change period to the 250 hour book.

Why do you feel it is time dependant and anything other than run hours?

There was along discussion earlier in the year and it was being much finally agreed that oil sitting in the sump means nothing far as the oil goes (it doesn't magically absorption moisture etc.)

I feel the biggest problem with time is that we run the engines once in a while and end up with unburnt fuel in the oil. So the longer this goes on the worst it becomes.

 

[mvweebles]

Why do you feel it is time dependant and anything other than run hours?

There was along discussion earlier in the year and it was being much finally agreed that oil sitting in the sump means nothing far as the oil goes (it doesn't magically absorption moisture etc.)

I feel the biggest problem with time is that we run the engines once in a while and end up with unburnt fuel in the oil. So the longer this goes on the worst it becomes.

Yes, I remember that thread. I was one of the people who noted that dinosaurs had been dead a long time without going rancid. Despite some searching, was unable to find any oil company that said their oil had an expiration date.

But I do feel (vs "know") that doing 100 hours over 10 years is harder on an engine than doing 100 hours over 10-weeks, though concede it's probably unrelated to oil breakdown vs moisture buildup without an opportunity to heat up and evaporete off.

In a perfect world, an owner would do an oil analysis to determine TBN and change their oil when that rose to a level that shows deterioration. For me, simply not practical so I am opportunistic about it - somewhere in the 200-250 hour range feels (that word again.....) about right. My oil starts getting black around 125-150 hours so I'm sure something is changing.

In the end, I just don't know many people in our class of usage who wear out an engine, meaning where more frequent oil changes would have made a material difference. Our engines do not die of old age but rather die unintentional deaths due to some bolt-on item revolting, usually an exhaust riser or an impellor committing Hari Kari.

I just don't worry too much about oil changes. It's part of a routine where I spend some quality time bonding with my engine, fawning over its aging blue paint and promising to be more conscientious. But in the end, I worry more about hose clamps and such.

Peter

 

[Steve DAntonio]

I have been reviewing oil analysis reports for about 25 years and as a result am firmly convinced we throw away a lot of oil that still has plenty of life left in it. Analysis is the only true way to know an oil's lifespan in any given engine.

Having said that, the 3116 and 3126 have some special oil needs, see attached. Originally, the 3116 & 3126 engines used 15W30 or 15W40. After premature clogging (air side) aftercooler core became an issue, Cat attributed the problem to viscosity indexers adhering to the blades of the turbo and aftercooler fins. To resolve the problem, Cat began recommending the use of straight weight oils only. The article is from Cat Engine News (1998). Note that a number of years after Cat made the switch, maintenance manuals continued to recommend multi viscosity oils.

If the engines are using multi oil, aftercooler cleaning is highly recommended. Check the turbo compressor wheel as well. I would also strongly recommend oil analysis at every change, for every diesel engine, it's cheap insurance. https://stevedmarineconsulting.com/wp-content/uploads/2014/03/FluidAnalysis143_Final.pdf

 

[Sundancer268]

I spent 26 years in the U.S. Navy in main propulsion engineering and on all of out equipment, we took quarterly oil samples and sent them off to the lab. Only once did we have to change engine oil in one of our diesel generators and that was due to salt water leaking in from the engine oil cooler. On my Duramax, I went over 10 years and 15,000 miles and changed it due to time, the Oil Sample I sent in said the oil was still good. I only have a little over 58,000 miles on the 2004 truck and only keep it to pull my utility trailer when I have to move my JD-1026R over to the dealer, only once since 2013 when I got the tractor. On my Motor Home with a Cummins 5.9 twelve valve, it gets changed every 4-5 years per the lab analysis recommendation. I send in a sample every fall just before the coach goes into the barn for the winter. All my other small Gas and Diesel engines are changed by the hour meter and that is every 200 hours per John Deere. 445 now has 1150+ hours since new 1994 and the 1026R has 370 since new in 2013. I have had any issues with any of my engines. Normal issues with the truck are not engine and transmission related, everything else has been a problem, brakes, instrument panel, Towing mirrors, Brake lines, fuel lines, fuel cooler etc. First and last GM product I will ever own. The Cummins and Allison in the Motor home has been flawless and the John Deere's are the best so far as I can see. A lab report is the only way to go if you have more than 5-6 quarts of oil. The nice thing with a boat is the engine is normally worked for quite a while at temperature and not like a car used for only short trips where the engine never gets up to temperature.

 

[La Sirena]

My main engine is a Cummins QSM11, takes almost 10 gallons of oil and I put about 650 hours on it each year. I change oil and filter every 300 hours. IMO, 100 hours is WAY too often. I send a sample to Blackstone each change unless I'm in the Bahamas. The oil looks almost new (still has a honey color) and the analysis is always excellent. I could probably extend it even more if I wanted.

I change the generator oil every 200 hours, and the wing engine every other year (maybe 100 hours). Likewise, the Blackstone reports are excellent.

The expense for 10 gallons of oil and a large filter is not inconsequential, about $300 and I do at least 2 changes per year. I also have to carry the new and used oil until I can dispose of it. If I did it every 100 hours it would be a lot of wasted money and take up a lot of space. I find Walmart to consistently have a good price on oil, but I'm not thrilled about the 3 gallon boxes they've migrated too

I have overlapped other maintenance items on the same interval so I'm not constantly in the engine room changing some filter or impeller. I go in and do several things at one time for efficiency.

 

[Don L]

I spent 26 years in the U.S. Navy in main propulsion engineering and on all of out equipment, we took quarterly oil samples and sent them off to the lab.

Must have been different navy than I was in.

 

[Capt Ray]

We have a 2000 Mainship 390 with a single CAT 3126.
I change its oil and CAT oem CAT filter every 200 engine hours. Fast 'n' easy job.
SAE 30 "straight 30" labels are found in more than one place on the engine by CAT. We use Delco or Rotella straight 30.

Transmission every 1000 hours. It always looks clean. Ours takes CAT's SAE 30 transmission lube.

Fuel filters are driven by the recording differential pressure gauge atop our Racor primary filter. Currently running 30 microns... though 3 different mechanics tell me six different opinions on 10 vs. 30 microns for primary! LOL CAT's secondary attached to the port side engine in a 3126 are 2 micron, I believe. We've been fortunate with good fuel on the east coast north and south... as well as on our loop.

I agree with the oil analysis recommendations. VERY reasonable cost!!! VERY valuable information. Just like my primary care physician wanting to do blood work every 3-6 months. Note that the analyzers like to know how many hours old the oil sample is, and if oil was added along the way and how much. Otherwise they tell me my information is less valuable without knowing all the details behind the sample(s) you are sending me. It is not a lot of money to get this testing done, and yet so few of us are as diligent as we could be. Think about resale value if you have all those records???!!! and predictive maintenance ability!

There are many more details and pics on our blog. Use the SEARCH tool to find posts on what we see and do. The SEARCH tool works well. https://shellerina.com/

 

[grandbanksbayfield]

I have a Lehman 135 in our GB32. My goal s to change oil when it starts looking dirty on the little piece of paper you use to wipe off the dipstick. That usually happens at about 100 hours. Even then, the oil still looks very clean when still on the dipstick. Slowing down 100 rpms barely makes a difference in your speed but my guess is that it prolongs engine life a lot. The overall cost of operating these craft is so great that it crazy to go around with very dirty oil.

 

[Csellars]

I have a cummins 6BTA5.9 liter. The manual says don't exceed 200 hours, I use Delo 15/40 heavy duty diesel motor oil. I worked on a commercial vessel with 4 Caterpillar 1500 HP diesels. We changed the Delo 15/40 oil every 500 hours (once a month). The engineers thought we should be going longer on the interval. Oil samples were sent out every month, no problems at 10,000 hours.