HST without fan

[rdsaustintx]

in the short term, you could probably get by with a 15 dollar 12 volt one. just tie strap it up there in front of the HST and run it off the 12 volt socket.

Good luck fitting it in there.

 

[J_J]

Hey, the electric fan could be a cheap alternative to spending to replace the original fan. Connect it in series with a temperature switch, so it comes on when the transmission starts getting hot.
Working as a mechanic for many years, I found an easy way to roughly check block or trans temperature. If you can touch and keep your fingers on the surface, It's 120F or less. If you can touch for three seconds, about 130F. If after 1 second, you go ouch, then it is 150+F. If you can spit on the surface and it sizzles, it's getting pretty **** hot.
The bottom line is, most hydraulic oils are safe to temperatures exceeding 250F. I have worked my BX23 hard enough that the cylinders have reached nearly 200F, and that is with the fan intact and turning at rated speed. I wouldn't be afraid to move the tractor from point A to point B, as long as you pay attention to the temperature.

I have to disagree on the max temp thing.

As the temperature of petroleum-based hydraulic fluid increases, its viscosity decreases. If fluid temperature increases to the point where viscosity falls below the level required to maintain a lubricating film between the internal parts of the component, damage will result.

The temperature at which this occurs depends on the viscosity grade of the fluid in the system. Hydraulic fluid temperatures above 180ï½°F (82ï½°C) damage seals and reduce the service life of the fluid. But depending on the grade of fluid, viscosity can fall to critical levels well below this temperature.

http://www.industrialtraininginc.com/hydraulic-fluid.htm

 

[Volfandt]

I have to disagree on the max temp thing.

As the temperature of petroleum-based hydraulic fluid increases, its viscosity decreases. If fluid temperature increases to the point where viscosity falls below the level required to maintain a lubricating film between the internal parts of the component, damage will result.

The temperature at which this occurs depends on the viscosity grade of the fluid in the system. Hydraulic fluid temperatures above 180ï½°F (82ï½°C) damage seals and reduce the service life of the fluid. But depending on the grade of fluid, viscosity can fall to critical levels well below this temperature.

Maximum Hydraulic Component Life

Kubota SUDT is an ISO 46 rated dino hydraulic oil w/a SAE viscosity grade of 10W-20. It has a flash point of 183

The UDT is also a dino hydraulic oil w/a viscosity grade of 20W

An old rule of thumb is a tractor's HST will run approx 100 degrees higher than the ambient temperature. So on a 90 degree day the HST and oil could be approaching 190 degrees!

Heat is one of the main depleters of an oils additive pkg. The hotter the oil runs, the shorter the usable lifespan of the oil.
Personally, I wouldn't run my HST very long without some sort of cooling and if I did I'd be changing the fluid out lickety split, after I immediately repaired the fan