Should I use detergent oil

[tundraotto]

15W-40 any brand

 

[dlundblad]

Rotella 10w30 or 15w40 in whatever style warms the little cockles of your heart.

Top off as needed, run it until hot and then change the oil. Within your next couple welding uses, run it until hot again then change it. Then yearly after that.

 

[Lubener]

I just purchased an older engine driven welder with an Onan 2 cylinder engine. The instructions say to use a detergent oil. As this is an older machine, I was wondering if I should use the recommended oil or something different. Also, what weight of oil would be best? This machine will not probably see 50 hours of use a year. Thanks for any recommendations.

SAE 30 detergent.

 

[bchannell]

While I'll stick to my normal mantra, "you could use water and it'd outlast the equipment it's on", meaning oil isn't all that important as far as brand, grade, vis. BUT, those engines are EXPENSIVE to buy parts for and a rebuild is usually out of the question, as it is prohibitively expensive. The brilliant government forced Onan to quit building them, what a darn shame! I had one on a JD318 and they are as bulletproof as any engine I've ever owned, which covers a lot of ground. They do seem to thrive on some sort of 40 wt oil. I used a lot of 15w40 in mine and if the fool I sold it too had taken even any kind of normal care of it, it would still be running. He was one of those that "tinkered" with things and couldn't fix a doorknob, but that's another story. Use any 30wt or 40wt oil and you'll be fine. I don't usually think a 50wt is needed, but not out of the realm of possibility. I don't think straight 30wt is worth the hassle to find and use. It's good oil, but usually not the manufacturers best product, so I'm wondering if they put a lot of effort in it. Add to that, that multi wt oils are so good, what's the reason to go single wt?
So there you have it, you could use almost any wt oil!
I was confused by your title "detergent oil", yes all motor oil is detergent oil. The only reason I can think of to use non detergent oil is an air compressor or where a manufacturer of some other type of equipment specifically recommends it.

 

[Creekside]

While I'll stick to my normal mantra, "you could use water and it'd outlast the equipment it's on", meaning oil isn't all that important as far as brand, grade, vis. BUT, those engines are EXPENSIVE to buy parts for and a rebuild is usually out of the question, as it is prohibitively expensive. The brilliant government forced Onan to quit building them, what a darn shame! I had one on a JD318 and they are as bulletproof as any engine I've ever owned, which covers a lot of ground. They do seem to thrive on some sort of 40 wt oil. I used a lot of 15w40 in mine and if the fool I sold it too had taken even any kind of normal care of it, it would still be running. He was one of those that "tinkered" with things and couldn't fix a doorknob, but that's another story. Use any 30wt or 40wt oil and you'll be fine. I don't usually think a 50wt is needed, but not out of the realm of possibility. I don't think straight 30wt is worth the hassle to find and use. It's good oil, but usually not the manufacturers best product, so I'm wondering if they put a lot of effort in it. Add to that, that multi wt oils are so good, what's the reason to go single wt?
So there you have it, you could use almost any wt oil!
I was confused by your title "detergent oil", yes all motor oil is detergent oil. The only reason I can think of to use non detergent oil is an air compressor or where a manufacturer of some other type of equipment specifically recommends it.

When the manual was written I’m betting that non detergent oils were still in fairly common use. Could be a valid question.

 

[bchannell]

Could be. You got me wondering when they started making engines and I found this history of the company. Pretty darn good read.
History of Onan