open system vs closed system

[1Lawman]

I just bought a John Deere 5093E.. I notice the aluminum hydraulic lines get very hot....My Kubota hydraulics lines stay cool..I'm told that is because JD has a closed loop system and Kubota has an open loop system and nothing is wrong with my JD..I know nothing about hydraulics..Is it normal for my hydraulic fluid in my JD to reach 180 degree F. normal operating temp.?

 

[oldnslo]

Where are the aluminum lines you mention? Closed center should not run any hotter than open center unless you are metering off flow for some function. If this is the pump case drain line it will be the hottest oil in the system due to the frictional losses in the pump and parts spinning in the oil bath.

 

[1Lawman]

Where are the aluminum lines you mention? Closed center should not run any hotter than open center unless you are metering off flow for some function. If this is the pump case drain line it will be the hottest oil in the system due to the frictional losses in the pump and parts spinning in the oil bath.

I'm talking about the lines in the back of the tractor right at the dual SCV's...If I grab the line tightly with my hand it is too hot to hold more than a couple of seconds..My dealer says this is normal..This is with nothing connected to those SCV's

 

[oldnslo]

Are these the lines going to the quick disconnects? If yes they should not be getting warm. If this is the pressure and tank lines from the SCV's then they could possbly be warm from leakage flow through the spools. Also if your tractor has electrical shift on these SCV's the pilot section used for shifting these may bleed of some flow. I would not expect them to be this hot but possible. Does the transmission housing get this hot also?

180 F is not unusual in mobile equipment hydraulic systems.

 

[Tx Jim]

According to Tractordata.com your tractor is open center. Any time hyd oil gets much over 225 degrees there's a problem be it open or closed center. 180 degrees is fine.

 

[oldnslo]

TX Jim is correct. The JD parts catalog shows double gear pumps used on the 5093E models so it would be an open center system.

 

[1Lawman]

Are these the lines going to the quick disconnects? If yes they should not be getting warm. If this is the pressure and tank lines from the SCV's then they could possbly be warm from leakage flow through the spools. Also if your tractor has electrical shift on these SCV's the pilot section used for shifting these may bleed of some flow. I would not expect them to be this hot but possible. Does the transmission housing get this hot also?

180 F is not unusual in mobile equipment hydraulic systems.

I don't know enough about hydraulics to know what you are asking..Yes they are at the quick disconnects..Dealer told me they will be the same temp. as transmission.. I notice they are hot when I've been mowing..

 

[1Lawman]

According to Tractordata.com your tractor is open center. Any time hyd oil gets much over 225 degrees there's a problem be it open or closed center. 180 degrees is fine.

I think that must be a mistake

 

[1Lawman]

If my dealer is telling me it's a closed loop system and in fact it is open that doesn't give me a real warm and fuzzy feeling..

 

[AGRIMAN]

I don't think Deere would put a closed center hydraulic system on a E series tractor. What you may have is a open center hydraulic system with closed center remote valves.

What kind of mower are you using?