Another someone has been reading and relying on AI answers.
No, not really, after watching a "tractor Time with Time" video, they were talking about one of his tractors running with higher temps and they installed a better cooler made me consider if it was an issue, especially those living down South. I simply asked if others had monitored this and did they make changes.
There has been some well-educated people that have replied respectfully and then there's the juvenile replies.
Is anyone Monitoring Their Hydrostatic Oil Temps During the Past Few yrs of Elevated Summer Temps?
- Thread starter LFP57
- Start date
Obviously, you seem know what you're talking about and I thank you for the respectful reply. It may be a non-issue but I thought I'd ask.The rule being quoted is based on the Arrhenius Rate Rule which predicts rate of chemical reaction as a function of temperature. The accuracy of that equation is well established.
In the case of applying that equation to hydraulic oil service life things get a bit murky.
How Heat Affects Lubricants: Understanding the Arrhenius Rate Rule
In the field of lubrication, temperature is a critical factor that can significantly impact lubricant life and machinery reliability. The Arrhenius Rate Rule offers a scientific basis for understanding and predicting lubricant degradation, enabling proactive measures that extend the life of your...www.machinerylubrication.com
The industry has arbitrarily established 140F (68C) as the standard for max service life. From there every 10C increase results in twuce as much thermal oxidation hence the "halves service life" prediction. That is not the death sentence most people attribute to it.
A more practical rule for mobile equipment is sump temps over 80C (176F) will have very real and practical negative consequences on service life. Likewise a high quality synthetic oil like SUDT2 will survive longer at 80C than a Grouo II based conventional oil. Intervals of higher temp increase oxidation but they dont immediately halve the service life.
As pointed out in the article I linked there are a host of other factors that play a role in service life. Dont get hung up on the "10C temp increase halves service life" and 140F metric. Its very deceiving language.
Dan
First of all you need to understand the issue a bit better. Lets start with the physical chemistry
Hydraulic oils in mobile equipment commonly operate at temperatures well above 140C. High end construction and agticultural equipment have temperature alarms that operate north of 200F. Engine oils see temps in excess of 240F. The oils are formulated for those conditions.
Kubota knows this and designed their systems and established their OCI based on those conditions. Measuring temperature tells you nothing useful about their OCI recommendation. If you are concerned you would be better served sending used oil samples off to a testing lab. If you see oil thickening or excessive wear metals its a sign your opersting conditions are excessively severe and the OCI needs to be shortened.
Dan
- Hydraulic and engine oils experience thermal degradation due to oxidation. Its a chemical reaction.
- The rate of oxidation varies with oil temperature. Thats true of nost chemical reactions and not just oil. Hotter temps increase the rate. The rule of thumb is the rate of a reaction doubles for every 10` C increase in temperature.
- The increase is basically constant across the entire temperature range of operation and nothing magic happens at 140F. An increase from 125F to 140F "cuts service life in half" just like an increase from 140 to 155.
Hydraulic oils in mobile equipment commonly operate at temperatures well above 140C. High end construction and agticultural equipment have temperature alarms that operate north of 200F. Engine oils see temps in excess of 240F. The oils are formulated for those conditions.
Kubota knows this and designed their systems and established their OCI based on those conditions. Measuring temperature tells you nothing useful about their OCI recommendation. If you are concerned you would be better served sending used oil samples off to a testing lab. If you see oil thickening or excessive wear metals its a sign your opersting conditions are excessively severe and the OCI needs to be shortened.
Dan
Last edited:
I look at it this way. Keeping the oil cooler won't hurt anything.
I rebuilt automatic transmissions for years. You could tell if the trans you were working on had a large air to oil cooler in the circuit by the lack of varnish in the trans, the lack of glaze on the clutch plates and how soft the seal rings were.
The transmissions in the best shape were those that were used at the drags. They had the snot beat out of them, but they ran the best fluid, deep sumps and an air to oil cooler that was in the 15K pound range. Shafts may be snapped from torque, but the clutches and seals were fine. THE most useless transmission cooler is the unit in the side take of the vehicle radiator.
I rebuilt automatic transmissions for years. You could tell if the trans you were working on had a large air to oil cooler in the circuit by the lack of varnish in the trans, the lack of glaze on the clutch plates and how soft the seal rings were.
The transmissions in the best shape were those that were used at the drags. They had the snot beat out of them, but they ran the best fluid, deep sumps and an air to oil cooler that was in the 15K pound range. Shafts may be snapped from torque, but the clutches and seals were fine. THE most useless transmission cooler is the unit in the side take of the vehicle radiator.
My little tractor, the fluid has gotten so hot that grabbing a ram was a big mistake.I'm (almost) surprised the paint does not look burnt! SUDT in it.
I really doubt a 70 degree day or a 100 degree day makes much of a difference.
I really doubt a 70 degree day or a 100 degree day makes much of a difference.