Recomended oil for Onan 4KW generator

[nadsab]

Hi

We have an Onan model 4KYFA26100K 4 KW generator in our Class C and were wondering what is the recommended oil type for it?

Thanks.

[tatest]

Because of the temperatures at which I operate the genset, I use 15W40, Delo or Rotella, whichever was available or less expensive when I picked it up.

[DrewE]

The Logans wrote:
Which brings up another question, has anyone ever added a temperature gauge to the Onan 4000? Love to have one in the driving compartment...

Temperature of what on the generator--cylinder head, oil, exhaust gas, ambient temperature around the generator, or...? Obviously there's not really a need for a water temperature gauge for an air cooled engine that has no coolant water.

[rjstractor]

tpi wrote:
Onan manuals are always an interesting read. There is an Onan standby generator using our Ford V10. 15W40 oil is recommended, and 5W30 is only recommended to 50 degrees F. FWIW they also call for cylinder head rebuild at 1000 hours (or two years whatever first) on the V10. 1000 hrs. translate to 30,000 40,000 miles of typical driving? Ummm don't think I'll be pulling the heads..

A stationary generator application is a completely different duty cycle than a vehicle, so I wouldn't think you could even translate hours to miles driven. It would be interesting to see how many hours the V10 would run in a generator application.

[The_Logans]

Which brings up another question, has anyone ever added a temperature gauge to the Onan 4000? Love to have one in the driving compartment...

[Marine_By_Choic]

nadsab wrote:
Great thanks.

Just curious - if the oil is low, or generator too hot, will it automatically shut down after running for an hour or so?

Yes

[ron_dittmer]

I use what is specified in the owners manual with regards to viscosity. But I can't recall off the top of my head what that is. I recall it is a straight-weight oil. Given we don't camp in winter, our see no reason to deviate.

I use full synthetic in our 2007 Onan 4000 because synthetic does not burn as easily as conventional oil. So if there is an oil-burning condition, the full synthetic provides me a little more safety margin. If a catastrophic failure occurred, for example the oil drain plug is loose and falls out, the residual coating of full synthetic will provide a little more lubrication while I am wondering why my generator got clanky and decide to turn it off.

If you wonder, the answer is "NO", that did NOT actually happen to me.

[Vulcan_Rider]

tpi wrote:
I think passenger car XW30 synthetics are a tad too light.

And I think that statement just unnecessarily confuses the issue.

I too think that you should NOT use any oil where the first number is below 10 but that does not eliminate all "passenger car synthetics".

Given the situation, an air cooled gas engine often runs when the outside temp is really high, a 10W40 or 15W40 would be preferred for most people, I think.

[tpi]

Onan manuals are always an interesting read. There is an Onan standby generator using our Ford V10. 15W40 oil is recommended, and 5W30 is only recommended to 50 degrees F. FWIW they also call for cylinder head rebuild at 1000 hours (or two years whatever first) on the V10. 1000 hrs. translate to 30,000 40,000 miles of typical driving? Ummm don't think I'll be pulling the heads..

To answer your question-in warmer conditions a good cheap oil is 15W40 Delo or Rotella. I use Mobil 1 0W40. I think passenger car XW30 synthetics are a tad too light. Maybe mixed 50-50 with the same brand synthetic XW40 would really get it about right-a 30 weight on heavier end of spectrum.

[ericsmith32]

SAE 30 32 to 100+
15w-40 10 to 100+
10w30/40 0 to 100
5w-30 - -20 to 50

The latter numbers is the temp range... per the manual. I ran Rotella 10w30 last time around 50 hours with no issue's. I put Pennzoil Ultra 5w30 in it this time. If your using synthetic's probably any range will work but with dino juice I'd stick to the list above.

Just don't hit the start button filling it up!

[navegator]

Some of these generators are splash lubricated, no oil pump and if the oil is to thin there will not be enough viscosity to prevent metal on metal, use 30W or what the manufacturer specifies.

navegator

[nadsab]

Great thanks.

Just curious - if the oil is low, or generator too hot, will it automatically shut down after running for an hour or so?

[Vulcan_Rider]

My Onan 4K recommends 30W or 10W30 but these things tend to run VERY hot so I use 10W40 synthetic.....which is the recommended oil weight for most air cooled motorcycles.