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Stretching Generator Oil Change Interval

Discussion in 'Generators' started by DOCKMASTER, Jul 21, 2025 at 5:16 PM.

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  1. DOCKMASTER, Jul 21, 2025 at 5:16 PM
    #1
    DOCKMASTER

    DOCKMASTER Senior Member

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    Do you stretch your recommended oil change interval on your gen by using synthetic oil? My NL 9kw and 20kw gens call for changes every 200 hours. No mention of difference between dino oil or synthetic or even a blend. Curious if folks are stretching these intervals using synthetic oil? The changes are simple are fairly inexpensive. That being said, sure seems like 200 hrs comes up pretty quickly. Especially on my 9kw which runs virtually any time we are off shore power.
  2. Capt Ralph, Jul 21, 2025 at 5:59 PM
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    Capt Ralph

    Capt Ralph Senior Member

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    Yes, We are using all synthetic on NL 12, 20, BMZ 20 (Isuzu 4LE1) and a kluge D1105, 9.
    Oil labs are coming back perfect past 300+ hours.

    I believe it was the synthetic oil that saved that D1105 when an intake valve stuck open and fuel washed the lung. The 9 is now all together yesterday and running great & strong.
    Yep, I under loaded a 9kw. Frack Me (FM).

    I queried NL years ago about synthetic. Official statement was dino oil was only approved under warranty.
    After that, no comment or concerns.

    We are a big believers in synthetic oils. Just wish it was available in CF-2, 40.
  3. Capt J, Jul 22, 2025 at 9:54 AM
    #3
    Capt J

    Capt J Senior Member

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    It depends, oil should be changed annually. But if you're putting those kind of hours on a trip in a short period of time (a month or two etc,.), I think you can go longer than 200 hours. Best to see how the oil is, color, if it drips off of the stick (seems to have lost viscosity). That being said, I can do an oil change on a generator in 15 minutes, sometimes less on most of them, if I know exactly what tools I need.
  4. Pascal, Jul 22, 2025 at 10:09 AM
    #4
    Pascal

    Pascal Senior Member

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    I usually run 200-250 hours on the Cummins powered Ohnos or my Isuzu powered Norpro. But indeed once you have everything handy and setup, 30 minutes is all it takes incl racor and sec. No big deal
  5. Capt Ralph, Jul 22, 2025 at 11:09 AM
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    Shopping for oil and filters is depressing enough.
    Dragging a pail of oil on/off the boat.
    Disposing of old filters and oil.
    Cleaning up.
    15 to 30 minutes uh?

    During our vacation, we ran our gen-sets over 1000 hours.
    The Isuzu received 3 oil changes while deployed, while anchored, in a hot engine room.
    On board; fresh pails of oil.
    On board; big box of new filters and oil-sorb pads.
    On board; empty pails for the used oil and used filter storage.

    That is a lot of logistics time and labor.
    I know some resources may be easier for Dockmaster in AK, but during and after his time moving south, his logistics will become more painful.

    Removing one or two oil changes a year can help keep an old back happy.
  6. Capt Ralph, Jul 22, 2025 at 11:15 AM
    #6
    Capt Ralph

    Capt Ralph Senior Member

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    In my opinion (IMO), Synthetic oils may offer a lil longer oil change interval but I believe it offers better engine protection. Greater protection when Bo-Bos happen over dino oil.
    Here is where I use my common term; More forgiving..

    Here is when oil lab reports are a must when extending change schedules and when Bo-Bos happen.
    When in doubt, oil labs have better answers.
  7. Capt J, Jul 22, 2025 at 2:09 PM
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    Capt J

    Capt J Senior Member

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    We're talking about a 5 quart oil change. Not 50 gallons! hehehehee IF the generator has a drain hose or better yet a oil pump connected to it, it can be drained in 2-3 minutes, at the same time you can change the oil filter, adding the new oil takes the longest of all of it. But I can knock out a generator I have done before with good access in 15 minutes pretty easily..............For the oil change itself, if you're on a trip, the only thing I'd be disposing of would be the filter and diapher, the oil can stay in the 5 gallon drain bucket until I get back to home dock and there's room for 3 generator changes. Unless the marina has a place for it. But the only reason I see that many hours is if you're on the hook and running the generator non stop.
  8. Capt Ralph, Jul 22, 2025 at 2:41 PM
    #8
    Capt Ralph

    Capt Ralph Senior Member

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    I think your missing my point.
    Yes, My gen-set oil changes are complete in minutes.
    Getting the oil & filters in your hands, then on/off the boat and disposal takes time also. Sometimes the worse part of the job.

    Do you charge your customers 15 minutes for changing gen-set oil or you add up all the time I'm trying to illustrate.

    Yep, for over 6 weeks.
    You forget, we don't touch land when we deploy.
    Why go into aqua space to get aweigh, and still make landfall to mingle with, what your escaping from.
    I had a great visit on a Dinner Key dock.
    Two fuel docks.
    One barge fuel stop (that was cool).
    One waterfront house visit by Mako.
    One dock night at Port Canaveral (never again).
    One dock night at Safe Harbor, Ft Peirce (maybe again).
    Naw, my feet never touched land.
    Last edited: Jul 22, 2025 at 2:47 PM
  9. DOCKMASTER, Jul 22, 2025 at 10:15 PM
    #9
    DOCKMASTER

    DOCKMASTER Senior Member

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    My 9kw NL uses a Lugger diesel. It takes 4 qts. of oil on a change. Yes, I'm plumbed to a Reverso pump. It takes me about 30 mins to change the oil except the time to go to the store and buy the oil if I don't have it on hand. I could do it faster but I take my time and tape a bag to the filter and punch a hole in it to drain it before I remove it. My only complaint on the gen set is the horizontal mounted oil filter which makes a mess if you don't drain the filter before unscrewing it. So time and expense is not really the issue. I was just curious as the interval seemed like it would cause some to change oil often if you are running gen 24/7 on extended trips.