Does anyone know the maximum operating temperature for hydraulic oil in an M5111? I have asked my dealer and emailed Kubota UK but no one seems to know. As a bit of background - I was cutting hay this year and the PTO was really hot I checked the tractor with a laser thermometer at 87C (188F). I have 1 month warranty left on the tractor and really want to know if this temp is too high before the warranty period end. Many thanks
M5111 Hydraulic oil temperature
- Thread starter David Wayze
- Start date
For what it's worth, my M5660 rear end temperature runs close to 160⁰ F after a day of mowing in the summer.
TheOldHokie
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General rule of thumb is for optimal efficiency sump temperature in a pure hydraulic system should be no more than 80C. That's ideal and not cast in concrete and does not mean it cannot go higher at times.
For a transmission that number is more ike 100C. So you are hot but not crazy high. Gear oils are specified and tested at 100C for a reason.
It also matters where you measured the temperature. A major function of the hydraulic reservoir is to cool the hot return oil. Is your 87C number the sump temp or something else?
Dan
I wouldn't worry about that temperature, hydraulic systems in a tractor do get hot when working. What was the ambient temperature when you reached this temp?
Modern synthetic fluid and seals will withstand a lot of heat without degradation. For example, Allison allows for converter out temperatures to reach 300f intermittently in their heavy duty automatics.
Rodger
Modern synthetic fluid and seals will withstand a lot of heat without degradation. For example, Allison allows for converter out temperatures to reach 300f intermittently in their heavy duty automatics.
Rodger
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I recall references here on OTT about operating temps reaching ambient temperature plus 100F.
Don't know validity or precision, or where the temperature would be measured.
As Dan mentions, location of the measurement could be important.
Don't know validity or precision, or where the temperature would be measured.
As Dan mentions, location of the measurement could be important.
Thanks for that I hadn't thought about the location of the reading. My mower requires the pto to be disconnected to put it in the transport position and when I did this it was very hot to hold. I don't remember it being that hot before. The ambient temp was around 25c (77f) - which is hot for here!