Motor Oil for Hydraulic fluid

lzicc · Mar 30, 2019

I have a Thomas Skid Steer that I inherited from my Dad. It's a T133. I need to add hydraulic fluid and the manual is saying to use 10W30 motor. Is that really a thing? I never knew motor oil would work for a hydraulic system. I'm used to using UDT or plain Hydraulic fluid. I want to check prior to adding any. The manual says to use 10W30 API Classification SE/CD. Most motor oil meets or exceeds those specifications. Adding motor oil to a hydraulic reservoir just seems to easy.

Tx Jim · Mar 30, 2019

Engine oil was utilized for hyd system in several model/brand older tractors

denmis · Mar 30, 2019

My Bush Hog backhoe uses 10W30 motor oil to operate its hydraulics. I thought it was strange too, but it works.

lzicc · Mar 30, 2019

That's good enough for me. I remember back in the day, my dad had this old Allis Chalmers High lift and we would have to travel about an hour away to get hydraulic fluid for it since local places didn't have it. This skid steer if I remember correctly was purchased in the late 90's. It's in great shape. I know with my Kubota, they're very specific on using SUDT, so guess I figured it would some kind of specific hydraulic fluid for this skid steer. It would be so nice if 10W30 would be a standard. It's very easy to get and it's cheaper than hydraulic fluid.

lzicc · Mar 30, 2019

This may not be as easy as I thought. The CD stands for Diesel oil. Most diesel oils I am seeing are 15W40. I don't see any 10W30 with the CD rating.

ovrszd · Mar 30, 2019

If you don't use it in cold weather that won't matter. Then it might be a little stiff til it warms up a bit.

AllDodge · Mar 30, 2019

My Terramite calls for 10W40 and it is stiff when cold. I'll fire it up and let it run a bit before using and this helps.

lzicc · Mar 30, 2019

But will that mix ok with what is in there now which should be 10w30?

AllDodge · Mar 30, 2019

That shouldn't be an issue, and BTW found 10W30 Rotella at walmart

https://www.walmart.com/ip/Shell-Rotella-T5-10W-30-Diesel-Engine-Oil-1-gal/109014734

RjCorazza · Mar 30, 2019

lzicc said:
This may not be as easy as I thought. The CD stands for Diesel oil. Most diesel oils I am seeing are 15W40. I don't see any 10W30 with the CD rating.

SE / CD is saying gas or diesel motor oil. A 5w30 would also be fine. My bobcat walk behind called for 10w30 motor oil, but I ended up flushing it and using Kubota sudt2 to use the same fluid I use in multiple machines.