Dumb question - Fluid vs Oil?

[N80]

Getting a PTO chipper next week. Infeed roller is hydraulic with its own hydraulic pump. Manual calls for iso 46 hydraulic oil. I see hydraulic oil and hydraulic fluid available. Always use hydraulic fluid in the tractor of course and I realize hydraulic oil is not appropriate for that application. For the chipper does it make any difference?

 

[oldnslo]

For the chipper doubt it would make much difference unless your chipper has hydraulic clutches or brakes.

 

[Roadworthy]

I don't know that it matters whether you call it hydraulic oil or hydraulic fluid. ISO 46 is what you're after regardless of which name used.

 

[dirttoys]

Not a dumb question, I thought ISO 46 was light (10 15) weight oil with some additives. I would think aw 46 would be the same called oil or fluid. Call me out if incorrect please.

Best,

ed

 

[rScotty]

I tend to use the terms oil and fluid interchangeably on the forum & I get the meaning from context.
For the technical geeks, hydraulic fluid is any kind of fluid used in hydraulics - it could be glycol, or water, or any fluid.
Hydraulic oil is one of those fluids.
Here most of us prefer to run an oil in our tractor hydraulics.

 

[BeezFun]

The major difference is that hydraulic oil is flammable, hydraulic fluid is not (or nearly not). The difference has gotten blurry because there are fire resistant petroleum based products. In WW2 they had problems with hydraulic oil used on planes and ships starting on fire when they had a leak under high pressure, so they came up with alternatives that weren't based on flammable petroleum products. Hydraulic fluids can be based on all kinds of things like synthetics (Kubota's UDT), petroleum products (Tractor supply hydraulic oil), and clever combinations of things to make stuff like brake fluid that needs to not boil under high temperatures but otherwise act like regular hydraulic fluid for power transmission.

ISO viscosity standards are applied to petroleum and non petroleum based products. An example is Kubota's synthetic hydraulic fluid which is not petroleum based but has an ISO rating of 46. You can go to tractor supply and buy hydraulic oil that's usually ISO 32. Automatic Transmission fluid also has an ISO rating, usually 32. So it's important you buy a fluid that's the right composition as well as viscosity.

 

[N80]

Thanks guys. I did read on the description of the Tractor Supply hydraulic "oil" not to use it with wet brakes or in final drives. It looks like my local Tractor Supply only has hydraulic "fluid" in stock but it is ISO 46, which the chipper manual calls for, and it sounds like from what you guys are saying it might be overkill but still perfectly functional for this application.

 

[WranglerX]

IF hydraulic fluid is not oil what is it?

 

[Doughknob]

Yep. good question. the answer it "is" an oil. It is a petroleum product, thus an oil. The Kubota UDT is a petroleum product/oil. synthetic oil is still oil/petroleum - it is just a "manipulated" oil where most of the molecules are the same size (optimum size for lubrication.)

 

[BeezFun]

Examples of non petroleum bases used for hydraulic fluids include water, canola oil, propylene glycol, olefins, esthers, and silicone oils. There's a big push to use environmentally friendly and biodegradable fluids in tractors and marine applications, so we'll probably start to see canola oil based products.