Onan generator oil

[GalaxyGirl]

Hey guys, I'm about to attempt changing my oil for the first time . I have an Onan 20kw. Does anyone know how much oil they take?

[captddis]

5 quarts each of 30# or 15-40 Rotella or comp.

[GalaxyGirl]

5 quarts each of 30# or 15-40 Rotella or comp.

Ok thank you.

[GJH]

Depends on which Onan. The MDL4 20kw takes 6 quarts, and they recommend 15-40 for it. If that is the model you have, I have an owners manual I can e-mail.

[captddis]

I dunno. I have serviced MDL4 gens hundreds of times and never had one that more than 5 qts.

[saltshaker]

I put 5qts of 15-40 Rotella in each of mine with a filter change. Pretty sure they drained completely prior to refilling.

[GJH]

Well that's what it takes including the filter, if pumped dry from bottom of sump. Done it quite a few dozen times myself. Plus, that's what is in the manual for both the engine and the genset.

[MikeP]

I would: drain oil, install new filter, add 4 qts. Start/run for a 30 seconds, stop engine. wait a couple of minutes, check dipstick. Add oil to preferred dipstick mark - (full mark, 1/2 way between "add" and full, add mark, whatever.) I suggest filling to the full mark the first time. From then on you may find that lower (NOT below the min mark) works better as far as oil consumption. An optional method is to simply add oil, checking the dipstick after 3-4 qts and then continuing to add until dipstick shows full. Then start engine and recheck after stopping, top off at that point since level will be slightly lower after engine has been run/filter has filled.

I would personally not base an oil change on any fixed amount of oil the first time you do it on a particular engine since overfilling is a definite no-no. Once you have done the above, then you know what THAT engine will take at each oil change and then you can do the X quarts at each change. Actually, I always do as described generally in first two sentences (adding a volume of oil that I KNOW will be less than the final amount, then topping off per the dipstick), no matter how many times I have changed the oil in a particular engine. It's a habit I got into many MANY years ago.

[finatic]

I just did mine last week. Took out 5 quarts (it was down 1/2 before I started). I put back in 5 quarts of Valvoline HD 30, ran it and let it settle back, and added another quart to get her full (includes new filter).

[GJH]

I just did mine last week. Took out 5 quarts (it was down 1/2 before I started). I put back in 5 quarts of Valvoline HD 30, ran it and let it settle back, and added another quart to get her full (includes new filter).

There ' go.

Good advice from Mike P on a first time oil change. We don't know what model genset is involved here, so a little caution is a good idea.