Oil for Kohler 20RCA generator - says fully synthetic API 5W-30 rated SG SH or SJ

Where do you live?

Does it get below zero in the winter?

Over 100 in the summer?

I am in Texas so I would run 15W40 in the summer 5w30 in the winter.

15w40 > 5w30, 0w40, 10w30and 10w40 when it is burning hot outside.

I have no use for 0w anything unless it is freezing cold.

I would not run a 0w or 5w anything when it is over 90 degrees.

You just spent $14k saving $15 on oil so you can use the same stuff all year does not seem like a good idea.
 
Last edited:
z71bill said:
Where do you live?

Does it get below zero in the winter?

Over 100 in the summer?

I am in Texas so I would run 15W40 in the summer 5w30 in the winter.

15w40 > 5w30, 0w40, 10w30and 10w40 when it is burning hot outside.

I have no use for 0w anything unless it is freezing cold.

I would not run a 0w or 5w anything when it is over 90 degrees.

You just spent $14k saving $15 on oil so you can use the same stuff all year does not seem like a good idea.
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I run HPL HDMO CC 5W/40 in my air cooled 18kW generator year round. Great cold flow when below freezing & stout enough for our summers above 110F. No issues as of yet. Gets it’s annual service tomorrow
 
Use the factory swill for 5-10 hours and then right to Mobil 0W40. 5 quart jugs at Walmart are cheap and it’s always available.
 
z71bill said:
Where do you live?

Does it get below zero in the winter?

Over 100 in the summer?

I am in Texas so I would run 15W40 in the summer 5w30 in the winter.

15w40 > 5w30, 0w40, 10w30and 10w40 when it is burning hot outside.

I have no use for 0w anything unless it is freezing cold.

I would not run a 0w or 5w anything when it is over 90 degrees.

You just spent $14k saving $15 on oil so you can use the same stuff all year does not seem like a good idea.
Click to expand...
M1 0w-40 passes some serious approvals in some very high performance gasoline engines. porsche A40 comes to mind. for something that goes from idle to full load in mere seconds, i’d much rather that 0w-40 over some 15w-40.
 
JavierH19 said:
Pretty much any 30/40 grade will do. Google says it's a v twin kohler and they aren't picky at all. I have mag1 15w-40 in my 2006 v twin kohler zero turn but it never starts below 60 but 15w should be good to -13f I think but it'd struggle more in the winter. A 10w is good to -22f I believe.

If you want a great high zinc and phos oil you can constantly dump without it bothering the wallet mag1 10w-30 hdeo is great. At $2.79 a quart change it all you want, $45+ orders get free shipping. It has a balanced calcium and magnesium additive pack so you can use it in modern gas engines. I've bought lots of their 15w-40 and I'll be buying their dex 3 ATF too since it's the cheapest I've seen and I like doing spill and fills. I think I'll buy this 10w-30 for the escalade and outlander sport and keep running their 15w-40 in my old trucks.

https://www.lowes.com/pd/MAG-1-Mag-1-10W30-CK4-H-D-Diesel-Oil-2-5-Gal/5001933103
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That’s a killer deal on a 10w30 HDEO. Thanks for link.

OP: you could try HPL PCMO 5w30
 
MVAR said:
I run HPL HDMO CC 5W/40 in my air cooled 18kW generator year round. Great cold flow when below freezing & stout enough for our summers above 110F. No issues as of yet. Gets it’s annual service tomorrow
Click to expand...
If it is 110 degrees what is the best oil to use?

5W40 or 15W40?

Do you want oil that is good enough or better at about the same cost.

To me it is not even close 15W40 in high temps is better than 5W40, or 0W40

Winter I would not be as as concerned between 5W30, 5W40, 0W30 or 0W40, but if I use 15w40 in the summer I would need to swap it out in the winter.

I think the spread between the low and high number matter - smaller is better - more important in hot outside temps.

5W30 has 25
5w40 has 35
15w40 has 25
0W40 has 40

The OW40 and 5W40 are seen as a covers all temperatures no reason to have to change due to season - if that is what is important to a person they solve a problem - I don't mind swapping oil so I choose to use the better oil for a specific temperature.

YMMV
 
Those 0W-40 oils that carry an approval such as Mercedes-Benz 229.5 or Porsche A40 are not deficient in any way to a run of the mill 15W-40 in this application. You’re not understanding what is important here.

Hasn’t anyone ever explained to you what the winter rating means and also what it doesn’t mean?
 
z71bill said:
If it is 110 degrees what is the best oil to use?

5W40 or 15W40?

Do you want oil that is good enough or better at about the same cost.

To me it is not even close 15W40 in high temps is better than 5W40, or 0W40

Winter I would not be as as concerned between 5W30, 5W40, 0W30 or 0W40, but if I use 15w40 in the summer I would need to swap it out in the winter.

I think the spread between the low and high number matter - smaller is better - more important in hot outside temps.

5W30 has 25
5w40 has 35
15w40 has 25
0W40 has 40

The OW40 and 5W40 are seen as a covers all temperatures no reason to have to change due to season - if that is what is important to a person they solve a problem - I don't mind swapping oil so I choose to use the better oil for a specific temperature.

YMMV
Click to expand...
I run this HPL as it’s a very stout oil that also happens to have excellent cold flow characteristics for my standby generators zero to loaded starts.

This last year didn’t see much runtime (15hrs). The generator was still at the full mark on the dipstick when I serviced it this morning. Plenty of the air cooled generacs will consume 1/2qt in 24hrs. This one had a short 15min outage & one longer run but didn’t consume anything.

Run whatever you want but stay on top of the level. If it runs several hours for an outage, check the level after shutdown.

Also, the way you’re going about the winter ratings is a bit off. Try to look for a high HT/HS for the hot temperatures & a low cst for startup flow/ease of pump ability. The particular oil I referenced is a G4/5 blend with solid performance in both areas.
 
Had a 20 RCA natural gas Kohler installed in 2017. In NY, temps range from 0 to 100 on a rare occasion. Average 20 to 90. The specified oil is 5W20. I change the oil and put back a Kohler filter & 5W20 1X a year. Technician said to change plugs after 250 hrs. Same thing, exercise 20 minutes a week.
 
50yr Street Mech said:
Had a 20 RCA natural gas Kohler installed in 2017. In NY, temps range from 0 to 100 on a rare occasion. Average 20 to 90. The specified oil is 5W20. I change the oil and put back a Kohler filter & 5W20 1X a year. Technician said to change plugs after 250 hrs. Same thing, exercise 20 minutes a week.
Click to expand...
Perhaps I’m the only one who thinks this, but using an ILSAC 20-grade oil in 100 degree weather for a piece of mission critical equipment that protects your property is foolish. There is no reason to do so. Are you really concerned that much about fuel economy here? Besides a reduction in fuel consumption there are zero positive reasons for using a grade like that.
 
kschachn said:
Those 0W-40 oils that carry an approval such as Mercedes-Benz 229.5 or Porsche A40 are not deficient in any way to a run of the mill 15W-40 in this application. You’re not understanding what is important here.

Hasn’t anyone ever explained to you what the winter rating means and also what it doesn’t mean?
Click to expand...
“Do you want oil that is good enough or better at about the same cost.”

I am not saying compare the highest quality 0w40 with bottom of the barrel 15w40.

Spend about the same per quart and which will be a better choice in very hot temperatures ?
 
OK, I'm open for suggestions. I was just going by the book here. Throw a grade at me for temps between 20 F - 90 F. RARE occasion 0 F - 100 F. Hudson Valley, NY area. Yes, expensive piece of equipment, no doubt. I'm all ears to help save the Kohler that's in it. I'm no oil engineer.
 
See my post #17. Open the link and spend time reading the details. Not a cheap oil….but premium quality specific to small engines. I like it in all my Honda GX engines. Atleast 9 😉
 
Down there 5-30w would be fine. My old Generac, sold that place, 10 yr old unit ran fine on 5-30w WM Supertech full syth. just fine. New place with a Generac with an unknown history is currently on the same oil. I'm up in the ADK's with way colder winter temps so both of those units had cold weather kits on them. -20f in winter is not uncommon here. Only way I would run a 0w bottom number in my units is if they didn't have cold weather heater kits on them.
With proper oil changes the motor will most likely outlast the brushes in the alternator or other external components.
 
Thanks repairman. I'll use up what's left in the jug of 5W20. Have many jugs of 5W30 synthetic I use for oil changes on my 03' Toyota. Keep catchin them on sale from WM...Getting crazy now...like an oil hoarder crazy :) LOL Gotta stop for a few years !!!
 
repairman54 said:
Down there 5-30w would be fine. My old Generac, sold that place, 10 yr old unit ran fine on 5-30w WM Supertech full syth. just fine. New place with a Generac with an unknown history is currently on the same oil. I'm up in the ADK's with way colder winter temps so both of those units had cold weather kits on them. -20f in winter is not uncommon here. Only way I would run a 0w bottom number in my units is if they didn't have cold weather heater kits on them.
With proper oil changes the motor will most likely outlast the brushes in the alternator or other external components.
Click to expand...
What would happen? I use Euro 0W-40 year-round in my standby generator.

Is a 0W rated 40-grade too thin? Would a Euro 0W-30 be worse? Both have a minimum 3.5 HT/HS due to the approvals.
 
For me 0 bottom numbers get consumed more in stationary air cooled units. I can't speak to big liquid ones.
I've tried 0w in one Generac and it used oil, back to 5-30w and no more consumption. Now in recoil start portable units that get stored in cold unheated areas then that oil is a must in them to get them to spin over fast enough to start in 0f temps and those units rarely saw 80f.
If I was down south in the heat, with barely if any below freezing winter temps it would be at least a 10-40w oil if not 15-50w.
 
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