Recommended oil for a Cummins Onan 4000k generator

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Amsoil small engine 10w40 or Shell Rotella T6 or whatever else you recommend. It sounds like some guys use diesel oil. I think it takes a quart or less so price is not an issue.
 
Factory rec is 15w-40 diesel oil, but Amsoil small engine would be phenomenal for that engine due to its super low noack and it just being a great oil in the first place.
 
Amsoil be my first pick as always in the small stuff that formulation is strong.
 
Shell Rotella T6, in 5W-40

If it has a filter, and you can squeeze it on, the Fram 3600 / Purolator 20195 / Wix 51516 is 5 inches long,
verses 3 and a half for the 3614...
 
Originally Posted By: mattwithcats
Shell Rotella T6, in 5W-40

If it has a filter, and you can squeeze it on, the Fram 3600 / Purolator 20195 / Wix 51516 is 5 inches long,
verses 3 and a half for the 3614...


This. Those little filters are h**l to get off. Most any 0-40 or 5-40 diesel oil is fine. The Onan runs hot especially those in a RV compartment.
 
I ran M1 0w40 in my onan 4K "microquiet" as its pretty cheap and I always have a lot on hand.

Rotella will be fine if not great

No filter on that genset - splash only lubrication.

It does have a nice altitude adjustment on the carb.

It drinks like a sailor consuming about 1/3 GPH at a constant 3600 RPM even idling.





UD
 
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Originally Posted By: UncleDave
I ran M1 0w40 in my onan 4K "microquiet" as its pretty cheap and I always have a lot on hand.

Rotella will be fine if not great

No filter on that genset - splash only lubrication.

It does have a nice altitude adjustment on the carb.

It drinks like a sailor consuming about 1/3 GPH at a constant 3600 RPM even idling.

UD

Mine is the 5500, has a filter and runs at 1800 rpm. Much more effecient and quieter
 
Originally Posted By: FermeLaPorte
Chevron DELO would be a better fit since diesel oil is HDEO, AMsoil is boutique meaning just for show


Why do you think this?

Let's get a fix on exactly what this engine is, and I can recommend an Amsoil oil that is very stout and more suited to the exact generator application than a generic HDEO.
 
Originally Posted By: pkunk
Originally Posted By: UncleDave
I ran M1 0w40 in my onan 4K "microquiet" as its pretty cheap and I always have a lot on hand.

Rotella will be fine if not great

No filter on that genset - splash only lubrication.

It does have a nice altitude adjustment on the carb.

It drinks like a sailor consuming about 1/3 GPH at a constant 3600 RPM even idling.

UD

Mine is the 5500, has a filter and runs at 1800 rpm. Much more effecient and quieter


You sure about that?

The 5500's Ive run are 2400 RPM units.

Quieter nicer and a big step up from that 4K for sure, but I didn't think it had an 1800 RPM head ??

UD
 
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Any 15w-40, sae30 or 20w-50 will serve you well. It is all I use in onans.
I do not own your model, but I do one two.
The one is a 4.5kw the other a 5.5kw. both have quite a few thousand hot hard florida hours on them.
I only used sae40, 15w-40, or 20w-50. Ran "3600" filters and did 150hr drains.



harvey
 
I've always used 15W-40 in the Onan generator in the 3 motorhomes I've owned. I use Shell Rotella 15W-40 which is easily obtainable at any auto parts store or Walmart. With my first motorhome I called the local Cummins Onan service center and asked specifically about the Shell Rotella oil since it's diesel motor oil. They said it's a good oil to use in diesel, gas or propane generators.

However, I would like just go with what the owners manual says.

You should have it already.
 
Originally Posted by trod30
Id love to hear your recommendation. I'm guessing your Small Engine oil?



A 4000k generator is a 4 mega watt generator and will power your entire home and probably your entire town.

Would be a huge engine.
 
Originally Posted by trod30
Id love to hear your recommendation. I'm guessing your Small Engine oil?



A 4000k generator is a 4 mega watt generator and will power your entire home and probably your entire town.

Would be a huge engine.
 
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