Engine oil used for hydraulic system

[ZraHamilton]

I have a big dog diablo mp mower and it's time to change the hydraulic oil and filter. In the manual it says to never use hydraulic fluid in this system, and to only use motor oil. It recommends SAE 20W50 but it doesn't mention any specs the oil must meet. It says to change the oil and filter every 500 hours or annually. It gets about 150 hours a year on it. I was going to use mobil 1 15W50. Will the mobil 1 be able to last 2-3 years since it is synthetic and and meets several specs? I'm open to any other suggestions as well for the oil. Also, does anyone know why this system would use engine oil instead of hydraulic fluid?

 

[Chris142]

My case tractor uses motor oil too.

 

[SOHCman]

My exmark zero turn specifically asks for Mobil 1 15w-50, it even says so on the reservoir cap for the hydraulic system.

If it want's 20w-50 you could use the Mobil 1 V-twin motorcycle oil, it has even better specs and stouter add pack than the 15w-50.

 

[SOHCman]

as to why, I would guess because these systems need better anti-where than a hydro oil usually comes with.

 

[MolaKule]

Not necessarily a good system but, there you are.

Today's motor oils usually contain less AW than do hydraulic fluids now.

My preference would be the Schaeffer's Oil:

http://www.schaefferoil.com/documents/130-254-td.pdf

What you need is an ISO 220 fluid if they are specing a 50 Grade engine oil.

https://www.bobistheoilguy.com/viscosity-charts/

See 'salesrep' here on BITOG.

 

[The motor guy]

That's a straight 50 weight though. Some guys use their mowers when it's cold out.

 

[Click]

20w-50 for mowers from Amsoil 20w-50 Amsoil

 

[oldhp]

If you use 20W50 Harley oil the engine will need a chrome air cleaner.

 

[SOHCman]

Originally Posted By: MolaKule


Today's motor oils usually contain less AW than do hydraulic fluids now.



Had no idea! good to know.

Would the hydraulic fluid being straight weight be an issue?