NX series hydraulic heat questions.

   / NX series hydraulic heat questions. #1  

dusty3030

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Jun 4, 2008
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2,329
Location
West TN
Tractor
Kioti NX6010 Cab, Kioti RX7320 Powershuttle/ Cab, Kubota M7040 HDC, Kubota U35-4, John Deere 317G
If you have a NX series I'm curious of those who have noticed elevated hydraulic heat levels - do you or don't you have the factory third function installed on your tractor?

My theory is the factory third function, at least the one that was installed on mine, is a major contributor to the hydraulic heat that I'm seeing. The flow goes from pump to loader valve manifold, then to third function manifold, then to rear remotes, three point and finally returns to tank.

The factory kit installed on mine uses reducer fittings along with a much smaller set of hoses to connect the third function valve than the hoses / lines that go from the pump to the loader valve - loader valve to rear remote.

Since that circuit gets a constant flow of the bulk of the fluid the bulk of the fluid is constantly being heated.

I'm going to work on this some more with my infrared thermometer and measuring pressure at the loader valves versus the rear and report back.

99FB1E8B-3569-4E91-9C12-5802E9531434.jpeg
 
   / NX series hydraulic heat questions. #2  
The original lines are most likely 1/2" and when the dealer installed the 3rd function, used 3/8" line. While 3/8" will be just fine for the work ports, it's definitely not fine for the valve IN and OUT to the next valve.

I strongly suggest for you to replace those lines with the 1/2" ones. Your hydraulic system will appreciate.
 
   / NX series hydraulic heat questions.
  • Thread Starter
#3  
The original lines are most likely 1/2" and when the dealer installed the 3rd function, used 3/8" line. While 3/8" will be just fine for the work ports, it's definitely not fine for the valve IN and OUT to the next valve.

I strongly suggest for you to replace those lines with the 1/2" ones. Your hydraulic system will appreciate.

Crazy isn't it? Those lines came with the kit that the factory sent with the tractor. I'm stopping by the dealer today to see if they still have the elbow fitting that was removed in order to install the kit. If so I'm going to return to stock (take the third function out of the circuit for now) and do some measuring.
 
   / NX series hydraulic heat questions. #4  
I did the same mistake on my homemade backhoe. I have a single spool valve for the drive and a 4 spool for the backhoe, all fed from a 3/8" hose.

With 9 GPM available, I was trying to squeeze that through a tiny 3/8" hose. Shortly after, I swapped to 1/2", the temps went way down (can't remember exact numbers now) and the pressure with all the valves in neutral, dropped quite a bit as well.

Now imagine your tractor with 18GPM (accordingly to Tractordata), although I'm pretty sure that they're including the steering pump flow on that as well. In reality, that must be around 13 GPM, give or take. That's a lot of flow for a 3/8" and fittings.
 
   / NX series hydraulic heat questions.
  • Thread Starter
#5  
Stopped by my dealer today and they still had the elbow fitting to put back in the loader valve block. I had enough time tonight to take the third function hoses and reducers off and put the line back as it was before the third function installed. I went over what I am experiencing with the head mechanic and he wants a report back of what I have found. They installed the kit according to instructions and I don't fault them.
 
   / NX series hydraulic heat questions.
  • Thread Starter
#6  
5BE0337C-5073-4168-A5A1-7C0EFFC465D2.jpegF1E896B4-5FC5-49AA-98C4-87D402A4E3A2.jpeg

It was the factory 3rd function.
Same ambient conditions- mowing where I left off. I had 210 as high as 220 at the rear remote valve with factory fluid and the constriction of the factory 3rd valve and lines. This afternoon I had 169 at the valve after returning to stock, changed filters and refilled with Kubota SUDT 2.
 
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   / NX series hydraulic heat questions. #7  
That's pretty interesting results. I wonder though if you can actually get 1/2 hose fittings for the third function manifold. If they used 3/8 in the manifold, the manifold is likely restricted to 3/8 fittings and would serve as an impediment. If that's the case, changing out the hoses wouldn't make any difference.
 
   / NX series hydraulic heat questions.
  • Thread Starter
#8  
That's pretty interesting results. I wonder though if you can actually get 1/2 hose fittings for the third function manifold. If they used 3/8 in the manifold, the manifold is likely restricted to 3/8 fittings and would serve as an impediment. If that's the case, changing out the hoses wouldn't make any difference.
I concur- I started talking with Michigan Iron about their kit. I’m not going to use the valve I have now for sure.
What I’m wondering is if Kioti sent the right kit to begin with.
 
   / NX series hydraulic heat questions. #9  
I concur- I started talking with Michigan Iron about their kit. I’m not going to use the valve I have now for sure.
What I’m wondering is if Kioti sent the right kit to begin with.

I've got the factory third function on my NX, but I've never gone through the trouble of measuring the heat output. Of course, I learn something new every day!
 
   / NX series hydraulic heat questions.
  • Thread Starter
#10  
I've got the factory third function on my NX, but I've never gone through the trouble of measuring the heat output. Of course, I learn something new every day!

Look on the right side behind the step and see what size hoses yours have. I'm curious.
 
 
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