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
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....
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......
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.
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.....
^^^^^^^^^^^^ 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.
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.