Motor Oil for Hydraulic fluid

[lzicc]

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]

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

 

[denmis]

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

 

[lzicc]

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]

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]

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]

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]

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

 

[AllDodge]

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]

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.

 

[ray66v]

Hydraulic oil starts out as approximately 30w oil.

The difference between motor oil, hydraulic oil, hydraulic transmission oil, and automotive transmission oil, is what additives are put in it.

They can in theory, all be interchangeable in some applications that don't require special additives.

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.

There was no advantage for me to use 30w oil. It would cost me more than the hydraulic oil, and the hydraulic oil has the additives to help it perform better in a hydraulic system. So, I switched it to hydraulic transmission oil, at the first change interval.

 

[AllDodge]

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

 

[Gordon Gould]

I use 10W30 in my L3010 because of heavy winter use. Never had any trouble finding it. It even comes in Kubota branded jugs as it is called out as being suitable in many diesel tractors like mine.

My TD7G dozer uses 10 Wt motor oil in both the hydraulic tank and the power shift transmission.

gg

 

[Gary Fowler]

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.

 

[lzicc]

I did find Rotella T4 on sale at Autozone for $17.00 per gallon. Since it is being used for the hydraulic system, does it have to be diesel motor rated? You need diesel rate for diesel engines for compression reasons. I can buy a 5 gallon of regular 10w30 for $50 at Tractor supply. It's not diesel rated though, only for gasoline engines.

 

[AllDodge]

Unable to say for your app, but look at the requirements for the oil needed. There should be something that mentions API certification. A SN is for gas motors and CJ-4 is for diesel. The Traveller oil is rated as SN

BTW, does it use/leak that much oil?

 

[RickB]

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.

C rated 10w30 oils are not hard to find. At all. The D part has been superseded a handful of times, you are likely to find CJ-4 these days.

 

[lzicc]

In the manual it states to use 10W30 API Class, SE/CD. I would hope that most oils produced today would supersede those classes. I just don't want to mess anything up.

 

[RickB]

The second letter in API ratings is progressive. CD oils have been obsolete for years. Decades more l8kely.

 

[Gordon Gould]

In the manual it states to use 10W30 API Class, SE/CD. I would hope that most oils produced today would supersede those classes. I just don't want to mess anything up.

There is your answer right there - "S" for spark or gas "C" for compression or diesel. Either OK.

gg