Oil choice for larger Generac generator...

I picked up a gallon of Rotella T6 5W-40 on sale and I'll see how it works. A gallon jug will be good for two changes, but at $16 I might get two. I see Amazon Basics has a 0W-40, but I don't know much about it.
T6 will do fine. I run Delvac 1 5w40 in my gens … but have to watch for it to come on sale as it’s not a cheap oil.
Delo 10w30 is a thicker 30 and in my 19 HP lawn tractor now …
 
I did some research on the M1 0w-40 and it doesn't seem cheap or readily available around here. I'll keep looking. :)
Just for clarity … it’s the European Formula that’s only $23 at Walmart despite being A40 approved (and other).
ESP is the more expensive oil …
 
Hey guys. It's oil change time on my generator and I'm trying to decide the best choice in oil for year round use from what I have to use here. I'm also interested in some suggestions on if there is something better to use in future changes. The generator is a large, portable 15Kw model and I've just crossed the 30 hour threshold to change out the break in oil that I put in new. The break in oil is Generac conventional SAE 30. Here is the model information:


It's a 30HP v-twin OHV engine with a spin on filter and oil cooler. It's taken me a few years to get to those first 30 hours of use, but it does power the whole house when we have an extended outage. I'm in NH, and it can get pretty cold here, but also hot in the summer. I don't use it enough to change the oil every season, so I'm trying to find the best all around weight for 100 hour change intervals.

The manufacturer suggests SAE 30 over 40 degrees, 10W-30 from 40 degrees down to 10 degrees, and synthetic 5W-30 below 10 degrees. I am planning on using synthetic year round, and I've got a few flavors of Penzoil Platinum here to use. I've got both normal and "high mileage" 5W-30, as well as "normal" 10W-30. I was leaning towards the 10W-30, but I've been reading some suggestions of using synthetic 5W-30 year round from Generac, as well as some posters in this forum suggesting the use of synthetic automotive oils are not the best choice on these air cooled engines. I've also seen mention of the "high mileage" variants of automotive synthetics have a more ideal additive package for these engines.

I do also have a jug of Rotella T1 SAE30...but it seems not ideal for year round use. So, what do you guys think? Also, what are some other suggestions for future changes if the PP is not ideal longer term?

Thanks!

I have a 16k Generac (LP fueled) and I use M1 0-40. I do a single oil change every fall and new oil filter at the same time.
 
I have a 16 KWh Generac mounted on a pad and hard wired into the panel on my home. Mine is also hooked up to the propane tank for fuel. The manual says to use a synthetic 5W-30 oil.
It does a self test every other week for 10 minutes and about the longest it has run when the power went out and it automatically kicked in was for 2 hours. So it doesn't accumulate a lot of run time.
I think the capacity is only a couple of quarts. The house was built in 2018 and I moved in a year ago.It probably has the original oil in it still so I plan on doing an oil & filter change by October. A 5 quart jug of Castrol Edge should be good for the next couple of seasons.
 
Run 0w16 so you get the best fuel consumption possible. Or you could just use whatever oil you want that it specs and never worry about it because you will never use it enough to make a difference.
 
This is the first time I’ve read this here. You mentioned Pennzoil synthetic... The M1 is basically the same price at WM with the exception of their various rollbacks throughout the year. If your local store doesn’t have it, you can always buy it online.

Youd have to look online and be willing to pay a bit more , but I’d run Rotella T6 5w30 or Castrol Edge 5w30 A3/B4. Youre only changing it every other year or less. 0w40 would work as well, but it’s technically not in the manual if you’re worried.

Otherwise, any 5w30 or 10w30 synthetic will work.

When I looked last night, the M1 0W-40 was showing on Walmart for like $14.50/qt...but looking again I see the there are different flavors of it. I do see now they have the 5 quart jugs of the "European Formula". I also looked up the T6, but I was only finding it online in 10W-30, 5W-40, or 15W-40. I did finally locate the 5W-30 T6, but it's twice as much as the 5W-40. If 0W-40 is suggested, is there any reason 5W-40 T6 wouldn't suffice?
 
I did some research on the M1 0w-40 and it doesn't seem cheap or readily available around here. I'll keep looking. :)
If you've got a Walmart nearby, it's both cheap and available. About $23 for a 5QT jug.

It's on the thinner side of a -40, and meets a lot of long-drain specifications. It's a good product.
 
Run 0w16 so you get the best fuel consumption possible. Or you could just use whatever oil you want that it specs and never worry about it because you will never use it enough to make a difference.

My main concern is longevity of the engine. I may not run it for tons of hours, but since I've had it we've had several situations where we had no power for more than a day. I have well water so no power means no water and it's been a lifesaver. I just try to not run it constantly because it drinks gas like it's going out of style. I just get my two refrigerators and chest freezer back down to temp, and use the water as needed before I shut it back down. It generally runs in 2-4 hour intervals. I also try to make sure to remove load and turn on idle control so it idles for a few minutes before shutting it down.
 
I realize this, but since it's the first change on something I would like to last for a while and it was a significant investment, I thought I'd ask here for the best choice for an oil that would be used year round, and through greatly varying temperatures. I'm not looking for some magical oil that will reduce wear to nothing, just some advice from others in similar circumstances. :)
 
I thought I'd ask here for the best choice for an oil that would be used year round

You already have that oil, Pennzoil 5W-30. But as others have pointed out, M1 0W-40 is a stout, Air-Cooled-Porsche-Approved oil at a very reasonable price at Wally's. That, or any 5W-40 HDEO for your climate. The frame of your generator will rust before you experience any oil related issues with the afformentioned products.
 
Thanks. I was just holding off on the PP as my research suggested it wasn't ideal for a air cooled engine like the generator runs. I asked earlier, but is there any difference in additive packages on the HMPP that would be better for this application? I have a jug I bought in error not realizing the packaging difference, so I was going to use it up. I've ordered the Rotella T6 5W-40 so I'll hold off until that arrives and probably just keep the PP for the cars. Thanks guys for the information.
 
I use 10w 30 full synthetic in my smaller generator and mower.
Supertech, mobil 1 or QSUD
 
One last question guys. I've been having a conversation on this topic with a friend, and he warned me about the Rotella because of it lacking detergent? I'm now somewhat confused. I've also read about diesel oil like Rotella have MORE detergent than normal automotive oils. Is this something I should be concerned about?
 
One last question guys. I've been having a conversation on this topic with a friend, and he warned me about the Rotella because of it lacking detergent? I'm now somewhat confused. I've also read about diesel oil like Rotella have MORE detergent than normal automotive oils. Is this something I should be concerned about?
Lol.

No.
 
One last question guys. I've been having a conversation on this topic with a friend, and he warned me about the Rotella because of it lacking detergent? I'm now somewhat confused. I've also read about diesel oil like Rotella have MORE detergent than normal automotive oils. Is this something I should be concerned about?

Rotella has plenty of detergent.
 
VOA here of T-6 5w40, you can see the calcium is 1845

 
Back
Top