Oil temp guage on HST models ?

[Rmart30]

I thought about this this weekend while using my 4600 ripping up some foodplots and could tell the hydraulics were very hot for a 75* day.
Do any of the Kubota HST models come with a guage or overheat warning light for the hydraulics ? If not has anyone installed one? Most of the construction equipment I work on has either a guage or light for hydraulic temp. It shouldnt be too hard to install one.

 

[rbargeron]

Edit !
A gauge might be fun to watch, but probably won't give much information you would act on. The larger HST dissipates its heat to the 8-9 gal volume of SUDT in the gear cases and circulates that through a cooler. Short of a broken cooler line, there's not a failure mode that a gauge would monitor. The oil temperature probably varies over quite a range depending on exact location, so a single temperature gauge wouldn't give much of a picture of what's going on.

A car's automatic transmission oil circulates to the engine's radiator for cooling - and that's already up near 200!

HSTs do get warm - but they usually stay within the design range, unless there's some problem for which temperature is just a symptom, not a cause.

Edit: Refund line forms on the left - Dick B

 

[RaydaKub]

I drove my BX about 5 miles on Saturday, full throttle, pedal locked as fast as she would go. I noticed quite a bit of warm air coming up through the lever slots and around the seat. I was surprised that it was warmer there than any time I had been using the bucket the previous 3 hours and I was working it pretty hard for that. I would have been interested in knowing how warm it got.

 

[kuboman]

A gauge might be fun to watch, but probably won't give much information you would act on. The larger HST dissipates its heat to the 8-9 gal volume of SUDT in the gear cases. Cooling depends on circulation, thermal mass and cooling of the tractor chassis by the air around it.

Unlike the smaller units, the larger HST has no fan or external oil cooler - so it doesn't have a failure mode that a gauge would monitor. The oil temperature probably varies over quite a range depending on exact location, so a single temperature gauge wouldn't give much of a picture of what's going on.

Hydraulic machinery is often ok with operating temps of 300-400 F. An example is a car's automatic transmission - they often circulate their oil out to the engine's radiator for cooling - and that's already up near 200!

HSTs do get warm - but they usually stay within the design range, unless there's some problem for which temperature is just a symptom, not a cause. As always, prompt cheerful refund if info is bogus. Dick B

In reality every Kubota above the BX has an external air to oil cooler. And no hydraulic machinery will run very long at 400*F. Damage starts to occur over 200*F.

 

[rbargeron]

In reality every Kubota above the BX has an external air to oil cooler. And no hydraulic machinery will run very long at 400*F. Damage starts to occur over 200*F.

Edit: I've had 9 L-series kubotas - the L48 and L5450's have coolers - the other 6 have no coolers for hydraulic oil.

 

[rswyan]

I've had 9 L-series kubotas - no external oil coolers on any of them, unless you are counting the outside of the iron housings as the heat exchange surface.

Dick,

Are you sure there's not a line running to a steel tube that runs back and forth (side to side) in front of the radiator, but perhaps behind the debris screen ?

My Kubota B2910 has one ...

And if damage starts above 200 F what explains the millions of transmission cooler coils inside the water radiators of cars & trucks?

Coolant temps are (generally) held to just under 200 degrees ...

The higher the temp, the quicker the damage occurs.

The ATRA (Automatic Transmission Rebuilders Association) says that heat-related damage could be eliminated if fluid temps were held to 175 degree and under ...

 

[ccsial]

My L3400 has an oil cooler in front near the radiator. I can touch the top of the transmission case from the seat. That is my gauge. It gets fairly warm, but if it was too hot to touch I'd get concerned.

 

[rbargeron]

See edited post above about 3 L's with coolers, 6 without.

Point taken about transmission temps. But if manufacturers immerse their trans fluid heat exchangers in the end tanks of radiators, doesn't that suggest 200 degrees is an adequate cooling medium ? Is the margin really that small?

 

[V1Rotate]

I pointed one of those infrared thermometers at the transmission housing of my BX after about an hour of mowing on a hot afternoon. It showed between 180 and 185 degrees depending on where I pointed it.

 

[Rmart30]

Most construction equipment of the hydrostatic design (dozers, trackhoes, manlifts,RTFL's, bobcats etc) always have a hyd temp gauge and will run in the mid to high 200's in temp with some into the low to mid 300* range on really hot summer days and heavy working.
Most of the sending units for the gauges or lights are inline in the return side of the system or in the sump/hyd tank and Ive never seen in 20+ years of working on all types of construction equipment one that had multiples to monitor it in different locations.

I want to be able to monitor mine to give a baseline of what it normally runs and to tell when I am working it a little too hard. I found out quickly that it runs much warmer doing dirt work than it does with a rotary cutter. I was surprised that a gauge, or even just a simple hi temp warning light did not come standard.
If I can find a suitable location for mounting a gauge I will go that route for about $80.
If no suitable place to mount a gauge I will install a dash light or a buzzer hidden in the dash after some checks with the temp finder to see what degree sender to use for it.

It will be a fun inexpensive little project to do after I get the skid plates done.