Appropriate oil for Generac Generator

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3
Thread starter
Greetings, any help/advice would be greatly appreciated.

We just purchased a home with a Generac Home Generator that's fueled by propane. The instruction manual states-

"Use a high-quality detergent oil classified “For Service SJ or SH.” Detergent oils keep the engine cleaner and reduce carbon deposits. When changing the engine oil, be sure to use 5W-30 engine oil."

My first issue is with the SJ or SH. My research indicates that these are obsolete and that I am good with going with an SN but I want to be certain before I go dumping a new type of oil into generator. Second question is "Detergent oil". Is this simply referring to oil with additives?

Finally, any recommendations about a high quality, readily available oil to use that meets the above requirements?

Thanks!
 
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2,420
I have had a Generac 16KW for a decade. I did an early break in and moved from Generac filters to a Fram TG and have used M1 0-40. Yearly oil change even though I know it isn't needed. I also put a cheapo hour meter on it.

Meanwhile my Honda walk behind mower gets M1 0-40 for 3 years :ROFLMAO: Bas x x x x step child!
 
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1,634
Location
Americus, GA
I would imagine that Generac 5W30 syn, Briggs & Stratton 5W30 syn and Shell Rotella T6 5W30 would be good choices. The Generac and Briggs oils are specifically formulated for air cooled engines.
 
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4,553
Location
Pittsburgh,PA U.S.A.
JD940, please provide the following information if you want the members to give you the best answers to what oil to use:

1) Is it an air cooled engine, or is it a water cooled engine ( does it have a radiator like a car with a radiator cap and hoses to and from the engine to the radiator?

2) What state and city are you located in? This may not sound important to you, but the oil requirements for a generator in Arizona and the requirements for a generator in Main are different.

3) If there was a long outage, would you be available to change the oil every 50 hours of running (every other day) or might you be away from home and the other people who live there not be knowledgeable about how to change the oil, and therefore the oil may ran for more than 2 days without changing?
 
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24,841
Location
Upstate NY
Amsoil small engine oil should be good also. The air cooled engines are always a best effort at cooling. Cooling fins are a favorite place for mouses to build a nest.
 
Greetings, any help/advice would be greatly appreciated.

We just purchased a home with a Generac Home Generator that's fueled by propane. The instruction manual states-

"Use a high-quality detergent oil classified “For Service SJ or SH.” Detergent oils keep the engine cleaner and reduce carbon deposits. When changing the engine oil, be sure to use 5W-30 engine oil."

My first issue is with the SJ or SH. My research indicates that these are obsolete and that I am good with going with an SN but I want to be certain before I go dumping a new type of oil into generator. Second question is "Detergent oil". Is this simply referring to oil with additives?

Finally, any recommendations about a high quality, readily available oil to use that meets the above requirements?

Thanks!
Congrats on being a prepared homeowner.

The SJ, and SH service levels were current at the time the unit was manufactured. Consider them the LOWEST quality oil you may use. Using the newest, SN or SP oils will provide better protection. "Detergent" oil is referring to the oil having additives to keep the engine clean, prevent rust etc. Some engines, i.e. newly rebuilt aviation engines are run on straight mineral oil(non-detergent), with no additives during the break in process. You would never want to use a straight mineral oil in your generac.

Its hard to argue with the engine manufactures recommendations in general. As mentioned above, any synthetic like Mobil 1 or any of the others will provide good protection in the 5W-30. I run both of my natural gas powered units on Pennzoil Syn 10-30 and have it stock piled in my garage for those extended runs we all enjoy down here in FL.

As mentioned, there are some oils out there, aimed at the motorcycle market that are specifically designed for air cooled engines. I think you would be fine with a good Synthetic 5w-30 from any of the major players. You didnt mention where you are located. Those gen sets had a few issues dealing with freezing temps in the past. Let us know if that could be a factor for you and we can get into that a little more.
 
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3,235
Location
Ca.
something W30 will be fine.

I run my gensets in high ambient heat for long periods of time under relatively high load.
Been running M1 0W-40 in all my gensets for over a decade, and even in my water cooled diesels.
Its relatively cheap and easy to find.
Some run 24/7 for a week at a time getting hot fueled.

UD
 
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19
The SJ, and SH service levels were current at the time the unit was manufactured. Consider them the LOWEST quality oil you may use.
SJ was the last API classification before the Zinc and Phosphorus levels started being limited. I suspect the small engine manufacturers recommend their own brand of SJ rated oil because it is blended with a full dose of additives and will provide a little extra protection for the half (90% ?) of the population that never changes small engine oil. Bitog members' maintenance habits, however, will allow other "options" that will produce at least an equal and possibly better long term outcome.

My small engines all get non-SN rated diesel oil for the extra additives.
 
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914
Location
Pennsylvania
It sounds as if you may have one of the larger generators with a water cooled engine. Personally I use M1 10w-30 HM or Rotella T6 5w-40 in my air cooled generators. As for the "SJ or SH" recommendations, those were the minimum specifications at the time of manufacture. You should be fine with newer rated oils.
 
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3
Thread starter
JD940, please provide the following information if you want the members to give you the best answers to what oil to use:

1) Is it an air cooled engine, or is it a water cooled engine ( does it have a radiator like a car with a radiator cap and hoses to and from the engine to the radiator?

2) What state and city are you located in? This may not sound important to you, but the oil requirements for a generator in Arizona and the requirements for a generator in Main are different.

3) If there was a long outage, would you be available to change the oil every 50 hours of running (every other day) or might you be away from home and the other people who live there not be knowledgeable about how to change the oil, and therefore the oil may ran for more than 2 days without changing?
Thanks to everyone for the in-depth advice, very much appreciated!

1- Water cooled (Edit)
2- Birmingham, AL
3- I'm always home so oil can be changed every 50 hours during an outage.
 
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3
Thread starter
Wow, thanks to everyone for the in-depth advice, I greatly appreciate it!!! I can now check one more headache off the new home checklist.
 
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4,553
Location
Pittsburgh,PA U.S.A.
+1 on the Shell Rotella T6 5W-40

It is available at a lot of places including WalMart in 5 Quart jugs for a good price. If there are any Tractor Supply stores near you they probably would have it for the lowest price.
 
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