Changing /swapping Hydraulic fluid

[squonk 45,161]

Not sure where to put this as this is actually going to be about my Power King but it can apply to Horsies as well. 

 

I built my loader about 15 yrs. ago . Pretty much a std set up like a ARK loader with a belt driven gear pump, Uprights that double as the storage tank, 4 cylinders ect. I used AW32 hydraulic oil way back when. I haven't added any oil ever. no leaks. Haven't used it much the past 6 or 7 years. got it out last winter once and had to get it out with this past storm. I had mag heaters on both sides of the tank for a couple of days and the garage was about 35° when I started today. The pump whines when cold but eventually it goes away. Used the tractor about a half hour pushing the piles I made with the 953 back. I had to leave the King (Elvis) out side as I needed to move a few things around in the shop before bringing it back in.

 

It sat out side almost an hour in 10° weather with a 0° wind chill. When I started it back up the pump whined again and the loader was really sluggish. I want to change the oil to maybe automatic trans fluid or a different weight oil for the cold weather. I don't want to wreck anything. Do I really need to get "ALL" of the old oil out? What would be a good oil for cold weather? Calling all of the hydraulic EX-Spurts! 

[ri702bill 11,052]

8 minutes ago, squonk said:

I don't want to wreck anything.

Compatibility of fluids comes to mind. So that the seals are happy... A lighter weight hydraulic oil??? 

[ebinmaine 76,851]

8 minutes ago, ri702bill said:

Compatibility of fluids comes to mind. So that the seals are happy... A lighter weight hydraulic oil??? 

 

Agreed 

[squonk 45,161]

So far researching AW32 is a 10W oil. Haven't found anything better for cold temps. That's why I was thinking ATF. Maybe not worry about it. This was the coldest weather I've ever used this loader on. When we get a storm it's usually one of those wet snow near freezing temps ones. Not this single digit crap.

[WHX?? 54,077]

4 hours ago, squonk said:

AW32 is a 10W oil

This I did not know but it was suggested by PF Engineering, where the loader plans came from,  to use 10 weight. I have no idea what the loader builder @cschannuth used and he didn't remember. I have quite a few leaks, more on that in another thread, and when it got low I just put generic tractor hy fluid in it. fine in the summer but for pushing snow around real slow. It's now in the shop and undergoing upkeep and it's gonna get log splitter oil which is advertised as 10 wt. Not gonna worry about what was in it. Never gonna get it all out anyway.  

The big tractor when I did the 50 hr fluid change out I wasn't gonna buy their 900 a jug fluid so I used AW46 which is supposedly 20 wt. Sluggish yes in the cold and never gets warm. The HY system draws off the hydro fluid which the transmission casing acts as a huge heat sink. 

 

I would just stay with 32 Squonky. Always wondered if 32 would be better in say a 520 hydro for winter. They whine like crazy when first started in cold. 

What about 0w-20??

Edited 11 hours ago by WHX??

[oliver2-44 11,162]

 

Here is a comparative viscosity chart that cross-references the common SAE engine oil, SAE gear oil, and ISO VG (hydraulic fluid) grading systems.

Note that while oils on the same horizontal line have similar viscosities, they contain different additives and are not always interchangeable; 

 

Kinematic Viscosity (cSt @ 40°C)	ISO VG (Hydraulic)	SAE Engine Oil	SAE Gear Oil
32	ISO VG 32	SAE 10W	SAE 75W
46	ISO VG 46	SAE 15W / SAE 20	-
68	ISO VG 68	SAE 20W / SAE 30	SAE 80W
100	ISO VG 100	SAE 30	SAE 80W / SAE 90
150	ISO VG 150	SAE 40	SAE 90
220	ISO VG 220	SAE 50	SAE 90 / SAE 140
320	ISO VG 320	SAE 60	SAE 140

 

Back at the Power and Hydro plants turbine oil is rarely changed ie I replaced 50 year old oil when doing major rehabs.

A Conoco Phillips oil chemist recommended we use hydraulic oil as additive oil to our turbines to boos the gradually lost additives.

We also did additive testing every few years and on rare occasions had the oil company make us a special 5 gallon can of super additive oil.

 

So my 2 cents is to keep using a Hydraulic oil to get additives.  Then again garden tractor loaders are low pressure 7-800psi, so there not like the 3000 and 5000 psi modern industrial systems. So additives for pumps and valve surfaces aren't as critical.

 

[squonk 45,161]

The only other oil I know of is Meyer snowplow oil which is good to -40° But it's close to a Franklin a gallon! 

[JoeM 9,472]

I use 32 and not really noticing sluggishness. It was out all night at 2 degrees, I warmed it up just the engine above idle, and it ran okay. Whines a little at the start, but I am in no hurry. ATF I think is just a tad thicker. 

9 hours ago, WHX?? said:

 32 would be better in say a 520 hydro for winter.

I went premium tractor hydraulic fluid. It is a 10W-30 weight with all the right vitamins for the hydro.