How much oil should a generator burn?

zoulasNovember 8, 2012

I have a Cummins/Onan 20KW Propane generator. Just purchased new. With hurricane Sandy, the generator ran for 5 days. After 2.5 days, I stopped it and had to add 1/8 quart oil. After the second 2.5 days, the power came back and I had to add another 1/8 quart. At first I was startled at the oil consumption. I called the dealer I bought it from and he said its totally normal. I then called cummins and they also said its completely within spec. Was I too optimistic in thinking it should not be burning any oil? Thanks

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That is such a negligible amount, I'd be quite pleased.
Especially if it was running 24/7 or spent periods under heavy load.

Also, often you'll find some engines are more prone to burn off the "top" few oz. near the FULL mark relatively fast, but the next few oz. take much longer.

In all, you are talking about 8 oz. in 120 hrs. or 1 oz. per 15 hours.
Think how slowly you would have to squeeze an eyedropper to drip 1 oz. in 15 hours.

    Bookmark   November 8, 2012 at 5:23PM
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Yah, And you were on break in too. That engine is doing great, due for an oil change due to hours.

    Bookmark   November 9, 2012 at 6:51PM
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Totally agree. I'm of the old school where if an engine doesn't burn "a little" oil, I'm suspicious-particuarly a diesel.


    Bookmark   November 10, 2012 at 10:13AM
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This is my opinion, other may disagree? that engine might have break-in oil in it? if it does I wouldn't change it too early. Give the oil few hours to alow the engine to seal up. regular oil may induce oil burning if the engine had break-in oil in it. Cam shaft lobs could be damamged if break-in oil changed too early? I would read the owners manual before I would do any servicing?

    Bookmark   November 13, 2012 at 5:49AM
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Break in oil is pretty much a myth in this day & age.

If it's not "broke in" after 5 days, it'll never be broke in!

    Bookmark   November 13, 2012 at 1:48PM
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"Break in oil is pretty much a myth" Not COMPLETELY true, but majority manufactures don't use the oils with extra wear additive.

Honda recommends initial oil change 3000 miles with special break in oil. JD recommends 50 to 100 hours on the initial oil change on their high end equipment. So it's best to read the owners manual for your equipment. I personnel don't like changing the oil too early in any new equipment that's filtered. IF something was left in the oil or crap breaking off then IMO it's issue with that manufacture.

IMO On cheap not filter applications I probably would change the oil after couple hours use due to nothing catching anything suspended in the oil. But thats me Others may disagree?

    Bookmark   November 18, 2012 at 10:33AM
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I agree with RC on this one . Although perhaps not referred to as a Break In Oil by all engine manufacturers these days , most engines are supplied with premium multigrade specific oil quite often semi or full synthetic grade for break in of new engines. I also ensure to run in or extend the hrs of intial oil usage for this purpose on new units which have a source of filtration to pick up any metallic debris.

    Bookmark   November 18, 2012 at 11:14AM
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