Motor Oil for Hydraulic fluid

[lzicc]

So I can pretty much use any 10w30 for the hydraulic system. It holds 8 gallons, soon I am going to change the oil and filter and don't want to go broke. If I can buy it in the 5 gallons buckets, it will be cheaper than buying it the gallon.

 

[MHarryE]

Motor oil is great hydraulic oil but remember it’s expensive. Some equipment specified motor oil when it needs the properties. One thing to point out is standard multi-viscosity engine oils has viscosity enhancers that can shear down in the close clearances of a hydraulic system (possibly 5,000 psi in a hydro vs about 50 psi in an engine). Synthetics that don’t need viscosity enhancers work best - but are even more dear.

 

[arlen4720]

John Deere skidloaders used motor oil for sure at least till 2010 (that’s what year mine is). However, JD put out a technical document saying that since they don’t own the spec of motor, and it keeps changing, that they will no longer be testing motor oil for its suitability as a hydraulic fluid. The document also mentioned that zinc levels are are less than they were.
They have a fluid called Hydrau and Hydrau XR that they recommend in all equipment designed for engine oil as the hydraulic oil.
I opted for the Hydrau XR, which is a synthetic multi grade oil. It was almost like a different machine with the new oil...more responsive, and the starter spins it much faster in the winter, and it is much less cold blooded. They did extensive compatability testing with various percentages of engine oil, and it is safe to intermix.
You may want to look at it or something similar. It makes sense about the low zinc.

 

[Tractor Seabee]

My zero turn had 30w oil in the hydraulic system from the factory. The only advantage I could see for that is the manufacturer only had to use one oil on the assembly line.
.[/QUOTE
My zero turn uses 20W-50 motor oil and it is a bit hard to find. I wish I could use hydraulic oil because it is much cheaper than motor oil. Even Walmart Tech oil is $4 per quart or $8 per quart for synthetic. It needs 4 quarts to change it. Even with yearly changes and less than 100 hours, it gets really dirty so the detergents in the motor oil are definitely doing their job. I dont think hydraulic oils have detergent additive, just anti-foam and maybe anti-rust additives.

Gary, is the 20/50 for hydraulics? If so why not use hydraulic fluid.

Ron

 

[lzicc]

Remember though, I'm talking the hydraulic system and not the engine. I may be putting too much thought into this. When the skid steer was make, the motor oils were very basic back then. So I would think any type of 10w30 motor oil would work. My concern is damaging anything like seals, pumps, etc. but using the wrong oil. I think I am stuck on the mindset with Kubota. They are very particular on using SUDT when they state this in there manual. Now I have only owned and maintain fairly newer Kubota equipment, so that is my experience. BTW, to put a face with the name, this is the machine that I am working with. I put new tires on it last week. The old ones were in decent shape, but were badly dry rotted.

John Deere skidloaders used motor oil for sure at least till 2010 (that痴 what year mine is). However, JD put out a technical document saying that since they don稚 own the spec of motor, and it keeps changing, that they will no longer be testing motor oil for its suitability as a hydraulic fluid. The document also mentioned that zinc levels are are less than they were.
They have a fluid called Hydrau and Hydrau XR that they recommend in all equipment designed for engine oil as the hydraulic oil.
I opted for the Hydrau XR, which is a synthetic multi grade oil. It was almost like a different machine with the new oil...more responsive, and the starter spins it much faster in the winter, and it is much less cold blooded. They did extensive compatability testing with various percentages of engine oil, and it is safe to intermix.
You may want to look at it or something similar. It makes sense about the low zinc.

 

[arlen4720]

Remember though, I'm talking the hydraulic system and not the engine. I may be putting too much thought into this. When the skid steer was make, the motor oils were very basic back then. So I would think any type of 10w30 motor oil would work. My concern is damaging anything like seals, pumps, etc. but using the wrong oil. I think I am stuck on the mindset with Kubota. They are very particular on using SUDT when they state this in there manual. Now I have only owned and maintain fairly newer Kubota equipment, so that is my experience. BTW, to put a face with the name, this is the machine that I am working with. I put new tires on it last week. The old ones were in decent shape, but were badly dry rotted.

View attachment 598171

Yes of course I’m talking about motor oil as hydraulic fluid LOL.
What John Deere is saying is that the older oils had a higher level of zinc and other additives in them. Zinc was reduced because of harm to DPF systems. A 3rd party controls motor oil ratings.
They recommend their Hydrau product in these machines now because they control the spec, and can formulate it to be just a hydraulic fluid.
Jd does NOT recommend using their Hygard tractor fluid (similar to the SUDT). Because that is formulated for hydraulic oil, but also is a Final drive oil. Skid steers have a different drive system of course, and the pressures and flows are MUCH higher than a tractor.

 

[aczlan]

Gary, is the 20/50 for hydraulics? If so why not use hydraulic fluid.

Generally speaking, zero turns will use motor oil (often specifically calling for synthetic 20-50) as hydraulic fluid for the drive pumps and motors. Not sure if they are designed to use normal weight UTF, but for 4 quarts a year, I wouldn't risk it.

Aaron Z

 

[ray66v]

Don't know about other manufactures, but if hydraulic oil is used in a Terramite it will damage the transmission. Doesn't do it all at once and have verified by talking to Terramite service manager

While it is possible that perhaps some additive is needed, that is in the engine oil, or there is a part is not compatible with something that is in the hydraulic oil.

Is there anything written that backs this up?

 

[ray66v]

It would seem they chose 20w-50 motor oil, because the existing hydraulic transmission oils were not heavy enough? Perhaps the equipment runs too hot for 30w.

There appears to is a growing market to produce a 20w-50 hydraulic transmission oil for those applications. I see Amsoil has added it.

 

[mini14]

In my research on zero turn mowers, the weight oil used is usually determined by its use of or lack of external oil coolers, pumps with or without fans, and the overall capacity of the hydro system. some systems are overbuilt and some are underbuilt, some have large hydro tanks, some use smaller ones. I have had good luck using mobil 1 15w-50 in every zero turn mower ive owned. never had a hydro issue in thousands of hours usage (landscaper for 32 years). I currently own 3 hydro mowers all have mobil 1 15-50 in them and all originally came with 20w-50