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

[RBT]

Where do you live?

I think many generator failures are caused by a combo of dumb things - not just using "too light" of an oil.

I read a bunch of stuff from people in Florida running after a hurricane, high outside temps - and generators were failing.

1. They run near capacity of the unit
2. They don't change the oil.
3. They let the oil level get low.
4. They use a plain Jane 5W30 / whatever was available at Walmart.

You can do better by not over loading , change & check the oil no matter what oil you pick.

But - assuming you are running extended hours in hot summer temps why not move up and get some oil that will handle things

Good morning.
We live in DC metro area most of the year. We bought a very good generator (Kohler) because we have confidence in the brand based upon personal experience. The machine is relatively new and under warranty so I don’t see a need to second guess the recommendation. But that is just me. Also, the installer has a good reputation so I don’t believe the machine is maxed out when running, even with the central air going. In life I have found that sometimes when you over think things you don’t help and often cause problems you did not anticipate.

Have a good day.

 

[MParr]

Any off the shelf 5W30 synthetic will work fine.

 

[Panda87]

I read that " mess" Panda. The manual on my gas Kohler 20 RESCA calls for synthetic 5W20 & an OE filter. Made up my mind to use the last of the 5W20, in about 6 weeks, when my back heals a bit from L3/4 disc replacement.( Last 5W20 OC , been using 5W20 since new in 2017)....... Next OC going with synthetic 5W30 & OE filter. I'm in NY. Avg temps range from 25-90. Machine exercises 20min a week. Fortunately, not too many power outages. Maybe 1 a year. Utility Comp did a good job trimming back trees, and my service line is underground for 1,000 ft. I have JUGS of synthetic 5W30 in stock. I have 2 old Toyota's that use that weight oil. I like your " mess". Very helpful

I tried to look up what a resca was, but came up empty handed, so I’m assuming it’s a generator based on the rest of your post. I’m surprised that the small engine mfrs are starting to spec a 20wt! Sorry to hear about your back! Just had my shoulder extensively repaired last August. I’d imagine a back surgery is a tough one. 5w-30 would likely do just fine as that’s what’s spec’d for my 3500w genset, though I’ve switched to 5w-40 Euro now that break in is complete. It gets run pretty much maxed out running 15k and 13.5k AC units on my camper in the dead of summer. It’s pulling ~3400W @ 28.9A when the ACs are running full bore.

 

[Panda87]

Mobil 0W40 is robust and will stay a 40 weight (or possibly shear to a thick 30 weight) for the entire 50-100 hour interval. And you can use it year round and not have to worry about changing it before winter in colder northern states.

I’m a big fan of 15W40 as I live in Florida and have been without power for literally months of my life due to hurricanes. An SAE40, 10W40, 15W40, or 0W40, or 25W40 marine oil is ideal for generators that are ran for days on end at max load, 3600 rpm constant, in 90+ degree temps.

The manual in most of these engine manuals are written by a person that doesn’t really know oil. They won’t know what an ILSAC GF6-A 5W30 engine oil is (the majority of regular passenger car oils on the shelf) and why it’s not really ideal for a Florida/Texas summer in a generator.

I’m not here to really argue for or against 15W40. I will say, in my experience, ANY 40 weight, to include 0W40, offers a bit more margin for error over the ILSAC GF6-A 5W30 oils that almost everyone else is running in a generator.

Florida people use generators when it’s 90-95 degrees outside. Northern folks use generators during winter snow storms usually.

The power grid in Florida is very reliable and probably the most robust power grid in the entire country since the power companies have spent billions of dollars hardening it and replacing sections of it year after year after every incremental storm. Right outside my neighborhood, FPL has preemptively replaced every power pole with a much larger wooden power pole and every 4th pole or so is a now a concrete pole. The power to my neighborhood was buried to protect the lines. During Ian, a Cat4/5 storm, I lost power for only 2-3 hours I believe. Which is freaking impressive. As I was pulling my generator out of the garage, I suddenly saw the lights turn on in my garage. Had the generator handle in my hand as the power came back on. I did an about face and put the generator back in its storage location in the back of my garage. LOL.

Back to oil, southern folks should pick a Euro oil, and ACEA A3/B4 spec oil, or any 40 weight and call it good.

I’m glad you were able to get the lights back so quickly during Ian! If it were me, my OCD self would have fired up the genny just to give it an exercise run since I already went through the trouble of getting it out .

Agreed on the recommendation for southern oils. I run HPL 5w-40 Supercar/Euro in mine because it’s what I’ve standardized across the board in my fleet now, my 3 motorcycles excepted. My IR gun shoots the head of my genset after 20 mins at ~219 degrees F at 90 ambient at half load ~1750W with this oil. It’s an enclosed body inverter genset so I would have expected much higher. The oil is holding up well!

 

[football]

Winter vs summer use-

A generator ran in the winter might run at 30 degrees. In the summer, for me, the temp would be closer to 90 degrees. That’s a difference of 60 degrees. In my experience an air cooled engines oil temp is related to the outside ambient temp. So a generator ran at 30 degrees is going to have 180 degree oil while a generator ran at 90 degrees is going to have oil that’s 240 degrees.

5W30 oil that’s 180 degrees is far thicker than a 40 weight oil that’s 60 degrees warmer at 240 degrees. Which is why 5W30 is perfect for winter use.

 

[football]

I’m glad you were able to get the lights back so quickly during Ian! If it were me, my OCD self would have fired up the genny just to give it an exercise run since I already went through the trouble of getting it out .

Oh the gas cans were filled, and the generators (I own several) were pulled out and tested BEFORE the storm got here.

 

[50yr Street Mech]

20 RESCA is probably the same as 20 RESA, I dunno, there are a bunch of abbreviations on the manual, but they all have the same natural gas engine. 5W30 syn will be my go to for OC's thanks to you Panda ......Shoulder surgery is no walk in the park either. This is my 2nd back surgery in 5 yrs. I was 6' in 2020, now I'm 5'6". Discs are degenerating and shrinking. 36 yrs Gas Construction for local utility company + almost 50 yrs auto repair has done a number on me. Shifting towards " light" auto repair. Starting to get my feet wet in detailing instead. Retired from Utility in 2022, but damage is done. Another disc will crap out eventually, it's inevitable. They'll just keep throwing in " aftermarket" discs to keep me goin . But, they don't come with warranties .....LOL 1 yr for full recovery for each disc

 

[Panda87]

20 RESCA is probably the same as 20 RESA, I dunno, there are a bunch of abbreviations on the manual, but they all have the same natural gas engine. 5W30 syn will be my go to for OC's thanks to you Panda ......Shoulder surgery is no walk in the park either. This is my 2nd back surgery in 5 yrs. I was 6' in 2020, now I'm 5'6". Discs are degenerating and shrinking. 36 yrs Gas Construction for local utility company + almost 50 yrs auto repair has done a number on me. Shifting towards " light" auto repair. Starting to get my feet wet in detailing instead. Retired from Utility in 2022, but damage is done. Another disc will crap out eventually, it's inevitable. They'll just keep throwing in " aftermarket" discs to keep me goin . But, they don't come with warranties .....LOL 1 yr for full recovery for each disc

Oh man, that’s intense. Sorry to hear about the body breakdown. I’m only 37 and suffer much of the same, but mine are from military life. I can’t believe you’ve shrunk 6” through all that, that’s absolutely wild.

On a positive note, you can always go nuts with a full syn 5w-30 from Amsoil or HPL 5w-30 HDEO or Euro and not have to do any “light” engine maintenance for at least 100 hours of run-time!

 

[50yr Street Mech]

37 !!! You're still a baby !!!!! Military don't care. You're just a number, like I was. Hope you don't have anymore major issues. I'll be 59 in 5 months. Prayin for no more problems with you being so young.......I only do OC with filter 1X a year on that standby generator. IF we have an extended outage, ( which is rare, but does happen ), I'll do an OC with filter after power restored. No need for all that fancy oil. BTW, OC & filer is tooooooo easy on that machine. It even came with drain hose extension to reach way past the outside of the unit, and they installed a brass or copper oil valve instead of a drain plug. Just turn open the valve, and out the oil goes That's " light" enough for even me

 

[Panda87]

37 !!! You're still a baby !!!!! Military don't care. You're just a number, like I was. Hope you don't have anymore major issues. I'll be 59 in 5 months. Prayin for no more problems with you being so young.......I only do OC with filter 1X a year on that standby generator. IF we have an extended outage, ( which is rare, but does happen ), I'll do an OC with filter after power restored. No need for all that fancy oil. BTW, OC & filer is tooooooo easy on that machine. It even came with drain hose extension to reach way past the outside of the unit, and they installed a brass or copper oil valve instead of a drain plug. Just turn open the valve, and out the oil goes That's " light" enough for even me

Eh, I’ll be fine. The VA where I live has honestly been the best healthcare I’ve ever had in my entire life. My docs, nurses, mental health folks, radiology, physical therapists and more have all gone above and beyond in every aspect.

That drain tube sounds like the bees knees. My genny just has a rubber plug I pop out under the drain plug on the engine and I prop the body on some boards with the drain pan under it. Pretty mess free. That valve sounds like the Fumoto valves I put on my vehicles! Those things make oil changes (and drawing oil samples to send to the lab) an absolute breeze. I freaking love those little inventions.

 

[50yr Street Mech]

Glad you're getting good healhcare. Hope Trump doesn't screw that up for you. Yes, those valves are fantastic ! Happy that the whole set up came with the unit.

 

[z71bill]

Good morning.
We live in DC metro area most of the year. We bought a very good generator (Kohler) because we have confidence in the brand based upon personal experience. The machine is relatively new and under warranty so I don’t see a need to second guess the recommendation. But that is just me. Also, the installer has a good reputation so I don’t believe the machine is maxed out when running, even with the central air going. In life I have found that sometimes when you over think things you don’t help and often cause problems you did not anticipate.

Have a good day.

Not a horrible idea to stay with the manufacturers recommendation during warranty - 100 and 10% on OCI.

But - The manufacturer's recommendation is not the holy grail - it is the bare bones minimum you have to do to keep your warranty.

Do you realize and understand that? It is not the best you can do to maintain the unit - it is the absolute minimum you can do to still keep your warranty.

Do you think it would be "better" to change the oil at the exact point the manufacturer specifies - or do it at 75% of the hours?

Do you think it would be "better" to use the generic 5W30 the manufacturer requires or upgrade to a better oil?

 

[z71bill]

Yeah I’m not reading that mess.

Why not respond? Because you can't - so you deflect with a meaningless snarky comment.

You know we really don't disagree all that much.

I was clearly talking about hot summer temps - you rant about snowmobiles like I wanted 15W40 in the winter.

But I really don't want to argue - take it or leave it - it is all good.

 

[UncleDave]

Kohler 20KW RESC on Nat gas.

I run 0W40 in mine.

We've had 27 outages in the last 8 months ranging from 15 min to 12 hours.

Pulled the stick after every run and the oil is still at the top and so clean I can barely see it.

It used a little the first 100 hours, but Ive seen almost no consumption since.

 

[50yr Street Mech]

Kohler 20RESC / 20KW / natural gas. Manual calls for 5W20 synthetic in my location. Avg temps 25-90 degrees / 4 seasons. Will be switching to 5W30 synthetic as per many past threads regarding this machine. Warranty has long expired. I do use OEM oil filters and do oil changes with filter once a year. Thankfully, on average, maybe 1 - 3 hour outage a year. All depends on how well Utility Company trims back trees. They have been doing a great job in the last 3 years.

 

[RBT]

Not a horrible idea to stay with the manufacturers recommendation during warranty - 100 and 10% on OCI.

But - The manufacturer's recommendation is not the holy grail - it is the bare bones minimum you have to do to keep your warranty.

Do you realize and understand that? It is not the best you can do to maintain the unit - it is the absolute minimum you can do to still keep your warranty.

Do you think it would be "better" to change the oil at the exact point the manufacturer specifies - or do it at 75% of the hours?

Do you think it would be "better" to use the generic 5W30 the manufacturer requires or upgrade to a better oil?

Totally understand your point. If I lived in TX I would seriously consider a higher viscosity.

That being said, the unit has a good quality synthetic in it (Mobil 5w30 full synthetic) and I think that is much better than bare minimum. I have had terrific luck with their full synthetic oils across many vehicles and pieces of power equipment.

Have a good weekend.

 

[Sam_Julier]

Generac 10kw NG single cylinder engine

Generac specs 5W-20 full synthetic. I run Mobil 1 EP 5W-30.

During the last full load exercise cycle I ran it for 60 minutes. OAT was 93 degrees.

Oil filter temperature was 185 degrees.

 

[50yr Street Mech]

Yep, don't know why Kohler and Generac are pushin 5W20........but ....5W30 seems to be the winner in my book after all these threads. ........Maybe the 5W20 drug dealers were pushing that grade oil at the time...LOL....As soon as my back heals up, I gotta do an OCI on my Kohler 20RESA......Friggin replacement disc !!! Don't get old all you youngins out there !!!! IT SUX BIG MOOSE CO-K

 

[Panda87]

Yep, don't know why Kohler and Generac are pushin 5W20........but ....5W30 seems to be the winner in my book after all these threads. ........Maybe the 5W20 drug dealers were pushing that grade oil at the time...LOL....As soon as my back heals up, I gotta do an OCI on my Kohler 20RESA......Friggin replacement disc !!! Don't get old all you youngins out there !!!! IT SUX BIG MOOSE CO-K

Get better soon! I’m running 5w-40 in my genset and it’s running amazingly. I’m sure 5w-30 is fine, but I’m extra sometimes

 

[z71bill]

Yep, don't know why Kohler and Generac are pushin 5W20........but ....5W30 seems to be the winner in my book after all these threads. ........Maybe the 5W20 drug dealers were pushing that grade oil at the time...LOL....As soon as my back heals up, I gotta do an OCI on my Kohler 20RESA......Friggin replacement disc !!! Don't get old all you youngins out there !!!! IT SUX BIG MOOSE CO-K

Is there some EPA efficiency rating?

That is part of the reason car companies have switched over to 0W20 -
My 2007 Tahoe 5.3L VS spec is 5W30 - a new Tahoe 5.3L is 0W20

Has anything really changed?