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Oil question for Onan Generator

Discussion in 'Generators' started by Keysbearfl, Sep 2, 2012.

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  1. Keysbearfl

    Keysbearfl New Member

    Joined:
    Aug 29, 2011
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    Location:
    New Smyrna Beach, FL
    I was told by the previous owner of the 43 Hatteras I just purchased to use straight 40 weight oil in the engines ( 6V92's) as well as the 8KW Onan generator. The oil fill cap on the generator stars use D10W-30. So....what oil should I use for the generator. All the opinions I have received so far said go with the strait 40 weight.

    Any recommendations are appreciated.

    Thanks
  2. captainwjm

    captainwjm Senior member

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    Aug 17, 2010
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    Location:
    Islamorada , FL Keys
    That's what I do w/ my 8v92s and 20 kw Onan; for the same reason.
  3. Marmot

    Marmot Senior Member

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    And that "same reason" is ...?
  4. captainwjm

    captainwjm Senior member

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    Location:
    Islamorada , FL Keys
    used by previous owner
  5. RT46

    RT46 Senior Member

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    Location:
    Long Island, NY
    my Onan says SAE 30 or its ok to use 10w30 for colder temps.


    My gears take SAE 30 so i only have to carry SAE 40 and SAE 30 oil....
  6. Capt J

    Capt J Senior Member

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    Location:
    Fort Lauderdale
    In South Florida, I don't feel that using straight 40w in a generator is going to hurt anything. However, the manufacturer does recommend 10w-30 so it cannot hurt.....I've talk to Onan dealers here and they've told me that using straight 40w won't hurt a thing......but take it for what it's worth......
  7. Bamboo

    Bamboo Senior Member

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    Location:
    Palm Beach, FL
    My gen set gets straight synthetic 30 and the mains get straight dino 40. No reason to sweat the cost difference in dino/syn in the small amounts a gen set requires and it's worth the extra piece of mind IMHO.
  8. Capt J

    Capt J Senior Member

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    The 1 thing you have to be careful of with synthetic in older engines is they have a habit of causing oil leaks because the synthetic has a tendancy to leak past gaskets much easier (like valve cover gaskets) etc.....
  9. Bamboo

    Bamboo Senior Member

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    ^^^^^^^^^^^^
    Absolutely- but the amount I see on the under pan oil sorbs is tiny, and I've run synthetic for quite some time with no increase in oil consumption. It does crank more easily when it's Oct in Montauk. :)
  10. Capt Ralph

    Capt Ralph Senior Member

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    Location:
    Satsuma, FL
    May I ask where you get your straight Syn 30 w from?
  11. Bamboo

    Bamboo Senior Member

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    Location:
    Palm Beach, FL
    I mis-spoke; I used to use straight 30 (T1) but switched to Rotella T6 or Mobil 1- neither of which is a straight weight.