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

[John Galt]

I just had a Kohler 20RCA whole house generator installed with start up scheduled for next week by the certified Kohler dealer. All in, including a long and complicated 1¼ iron iron pipe run, was just north of $14,000 with permits and inspection fees. Factory warranty is 5 years parts and labor and I’m getting a service plan which includes internet monitoring. Obviously I want to keep the warranty valid.

I have watched some owner videos on this exact generator and they say, and so does the manual, that the oil needs to be checked and topped off after every 8 hours of run time and to use the specified grade oil because it has a higher zinc content. (?!) The fuel is natural gas. The unit will be programmed to run a self-test run once each week for 20 minutes. The manual says change the oil and filter every 150 hours or yearly.

The specified oil spec for my area temps is full synthetic 5W-30 with API Grade SG,SH or SJ. Any oil recommendations? I will want to change (2 qts required) the start-up oil after say 5-10 hours of operation but that won’t be included in the service contact but I want to stay in compliance with the manual/warranty. I see Kohler bottles their own 5W-30 syn oil but it’s near $18/qt. I’d like to get a 5 qt jug of something in compliance with the specs and reasonably priced. I’ll get the Kohler oil if I have to but geeze!

 

[JavierH19]

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

 

[BrendanC]

i put m1 0w-40 in all standby generators. excellent cold flow and great high temp protection.

 

[fantastic]

In a stanby generator any 5w-30 FS should make that last a very long time. However, being those were older specs with different requirements for the day I'd say find a 5w-30 Euro oil or a 0w-40. 5w-30 just covers such a wide variety of climates & with decent protection. If you're always in a warm climate maybe consider a 10w-40 motorcycle oil but make sure you are above freezing IMO.

5w-30 Mobil Truck & SUV, EP, or EP High Mileage for a slight viscosity bump. So many options...

 

[nwjones18]

With only a 2qt capacity I bet they do want you to check it every 8hrs.. Not much margin for consumption on something that can run as continuously as a generator. I'd run what they want you to during warranty, but like the 0w-40 recommendation after that. I also think something like 10w-30 Delvac extreme would be a good choice:

https://www.walmart.com/ip/Mobil-De...8?classType=REGULAR&athbdg=L1300&from=/search

 

[Rand]

The owners manual is from 2012?
From the online owners manual page 70

4.2.4 Engine Oil Recommendation Use 5W-30 or 10W-30 API (American Petroleum Institute) Service Class SG, SH, or SJ synthetic oil. Synthetic oil oxidizes andthickens less than other oils and leaves the engine intake valves and pistons cleaner.For the 26 kW model, 10W-50 extended-life synthetic oil is also available. This premium oil requires fewer oil changes. See theService Schedule for oil change intervals.

It doesnt mention anything about higher zinc..
I'd use a 5w30 syn, and out of warranty m1 0w40 or a thick 30wt.
it lists 10w50 for the bigger model..

 

[oil pan 4]

Closest thing I can think of that you might be able to get today is harbor freight has STP 10w-30 sj for $9 a quart.
Lowes and home Depot will likely have some briggs and Stratton 5w-30 sj rated oil but will cost as least $18 a qt.
Since most failures happen in less than 25hrs on new equipment just run the factory oil, change it after a few hours with high dollar sj oil then after 25hrs just run whatever.

 

[John Galt]

The owners manual is from 2012?
From the online owners manual page 70

It doesnt mention anything about higher zinc..
I'd use a 5w30 syn, and out of warranty m1 0w40 or a thick 30wt.
it lists 10w50 for the bigger model..

Yea that is it but dated 2/2021. The zinc issue was mentioned in a couple of maintenance videos and it seemed legitimate since I thought the newest standards required reduced zinc content as a condition of the latest API ratings. I use M-1 euro 0W-40 229.5 in our MB and have that on the shelf. I like it but maybe too thin/thick for an air cooled engine. Or more likely they (Kohler) just left the standard alone since it was good enough….

 

[Rand]

I like it but maybe too thin/thick for an air cooled engine.

What is too thin about a 40wt in an air cooled engine?

 

[John Galt]

What is too thin about a 40wt in an air cooled engine?

No idea on my end, I’m just trying to figure out what Kohler engineers are thinking. They recommend 5w-30 or 10W-30. And recommend an out of date API standard. I’m wondering why is that?

Since it is a totally enclosed and air cooled motor in a super well insulated (for sound deadening) enclosure I think a 0W for start-up would be ideal and a 40 weight for running and especially on shutdown where the 2 quarts of sump oil will be sitting, baking in a box slowly cooling down on hot summer days. Seems like severe service conditions and a euro oil with MB 229.5 and Porsche A40 approval would be best. Why Kohler sticks with an old oil spec is baffling. Kohler is offering a 10 year warranty special offer on this engine and generator right now so the oil they recommended is working. Winter here can get down to +5F every once in a while but 10-15F lows can be counted on almost every year at least for one overnight, summer 100F is it.

 

[kschachn]

No idea on my end, I’m just trying to figure out what Kohler engineers are thinking. They recommend 5w-30 or 10W-30. And recommend an out of date API standard. I’m wondering why is that?

Since it is a totally enclosed and air cooled motor in a super well insulated (for sound deadening) enclosure I think a 0W for start-up would be ideal and a 40 weight for running and especially on shutdown where the 2 quarts of sump oil will be sitting, baking in a box slowly cooling down on hot summer days. Seems like severe service conditions and a euro oil with MB 229.5 and Porsche A40 approval would be best. Why Kohler sticks with an old oil spec is baffling. Kohler is offering a 10 year warranty special offer on this engine and generator right now so the oil they recommended is working. Winter here can get down to +5F every once in a while but 10-15F lows can be counted on almost every year at least for one overnight, summer 100F is it.

They recommend it because it works okay. Sometimes those oil recommendations are not updated in manuals because, well, it worked fine then and it still works fine today.

But I also use leftover Euro oil in my OPE as well, lately it's been ESP because that's what I get now but it used to be a 0W-40. It can't hurt.

 

[berniedd]

Use the M-1 euro 0W-40 you already have with confidence. It will give better protection in your application than the 30 weight Kohler recommends. Someone here familiar with generator ownership and repair posted 1 or 2 years ago says his experience showed that 30 weight oil is inferior to running an air cooled gennie in an enclosed room in a hot climate vs a 40 weight.

 

[MVAR]

I use HPL HDEO Cold Climate 5W-40 in my air cooled 18kW Generac. Calls for a 5W-30 but the CC HPL flows really good & I prefer running a 40 over a 30 in air cooled engines that see >110 summer temperatures.

Also run this oil in lawn mower, classic bronco & will likely be running it in an F150 that’ll be delivered next week so it’s on hand & easy.

 

[mobilnissan1991]

Im running Mobil 1 V-Twin 20W50 in my 20kw Briggs natural gas unit with a Briggs Vanguard 35 hp that specs either 5W30 syn or 15W50. No problems in the cold and great viscosity for hot Louisiana summers.

 

[John Galt]

The owner of the Kohler generator dealership was here yesterday to review the installation by his crew (great job) and do the start-up. He made it a point to write down on the unit that 5W-30 full synthetic oil was to be used when topping off the oil level after every 8 hours of run time, and at least once per day (twice a day is better until I understand the oil consumption pattern) during an extended power outage.

He said any 5W-30 full syn was OK and didn’t really understand what I was saying about the SG,SH or SJ label. I happened to have a jug of Costco Kirkland full syn 5W-30 SN+ on hand that I use in my POS Buick and he said since it is API certified and Dexos II approved that it would be perfect.

But all said I think I’ll be topping off with M1 euro 0W-40 MB 229.5 that goes in my wife’s car. The latest guidance from Kohler on this engine is to change the oil once per year or after 150 hours of run time. Through a WiFi link they remotely monitor the system and can see oil temp and pressure, enclosure temp and hours. They (servicing dealer) can see additional data that is unavailable on my homeowners Kohler iPad monitoring app.

 

[4WD]

I use Redline 10W30 in one and Delvac 1 5W40 in others

 

[Dutchy491]

Amsoil Synthetic Small Engine Oil meets the SG, SH, SJ with high ZDDP that you’re looking for. I use the 10w30/40 in all my small Honda engines.
https://www.amsoil.com/c/4-stroke-power-equipment/12/?zo=331384

 

[Dutchy491]

I actually changed the oil today in my Red 3000is after a hard weeks work due to an ice storm knocking out our power for 3 days.

 

[MBBW]

Aren't the standards backwards compatible? What are we really talking about here?

 

[Owen Lucas]

I'd have an open bottle of the official Kohler oil around just in case anyone says you didn't use the factory stuff. Warranties can be denied for any reason.