Hydraulic over heats on 650 j

[Scott 650j]

I have a 2008 650j with 4800 hrs. Will run it bout 2 hrs and the hydraulic high temp light comes on, let machine cool for 15 minutes and can get about 2 more hrs and light comes on again. I have cleaned/ pressure washed radiator till it's like knew, changed filter, and this last time took valve body off and had tested. Shot with temp gun when light came on - valve body 220, tank 210, pump, 210, hottest cylinder 190, oil cooling side of radiator bout 160. Transmission side of Dozer/ tank runs 150-160. Any help would be greatly appreciated. One last question is there a screen/ filter inside the tank?

 

[HDMRice]

Since you have a temp gun, I'd do a temp differential across the hydraulic oil cooler. Measure the bottom, and then the top of the rad, and see what the difference is. Just to make sure you're getting proper cooling across it. I'm not seeing a specification as to what the differential should be, but I imagine its close to what the radiator should be doing. 5-10 degree's Celsius. Concerning the input hose to the cooler, there is an orifice at the control valve that potentially could be plugged.

Since you're getting that reading of 160F on the cooler, I'd imagine it isn't getting fed oil to be cooled.

 

[Scott 650j]

Where would the control valve be located? I had the valve body off and tested. Thank you for the reply

 

[JS300]

Wonder if it has a thermstat in the system. A buddy had same issue on a Case dozer and it ended up being a t-stat he didn't know was there.

 

[lantraxco]

Unless it was ordered with it or added on, I don't believe the hydraulic system has a cooler. The oil cooler in the radiator stack should be for the transmission only. At least that's my best guess without a service manual.

I gotta ask, what are you doing to heat the oil up? It's possible a spool not centering or a relief valve that's bypassing a lot can cause this. Or a very worn pump.

 

[JS300]

I should have read post better, my buddies Case was the t-stat on transmission side he was about to order a torque converter when he found out about the t-stat.
I had to change my tank sight glass awhile back and got a new one with a temp gauge built in. It normally runs 170-175. I would guess something leaking by and heating up oil as well. I wonder if it would get hot sitting at idle or say just using one function. Would the pressure relief valve being dirty cause the oil to get hot?

 

[Scott 650j]

Your exactly right no hydraulic cooler only transmission one. May be a worn pump , when I use the temp gun on it the pump is at about 210 where as the valve body was 220. As far as the pressure relief I had it tested when they tested the valve body ( it is attached to the valve body right ? ). Only heats up when pushing, it will actually cool down while idling or shutting down machine. I reckon next step I will pull pump off and have it looked at. What about where the filter screws in? Is there some kind of bypass there?

 

[lantraxco]

There is a bypass valve for the filter but it's low pressure and only opens if the filter plugs up or if the oil is very cold on startup.

 

[mred]

I have a jd450h. I have had same issue. If the oil is not low, look for operator problem. I tend to let cylinders bottom out. Oil goes thru bypass. Heats up the oil fast. That is why it cools down when not being used. It happens with me when I dig stumps, but not pushing dirt. I tend to operate the blade to much with stumps.
Per Jd MANUAL, for hydraulic oil overheats: 1. excessive load, 2. Operator holding hydraulic system over relief, 3. using low viscosity oil in hot weather, 4. restriction in oil lines or valves, 5. incorrect system relief valve pressure, 6. excessive leakage in hydraulic system.

I have to learn to return levers to neutral when not in use.

 

[HDMRice]

Your exactly right no hydraulic cooler only transmission one. May be a worn pump , when I use the temp gun on it the pump is at about 210 where as the valve body was 220. As far as the pressure relief I had it tested when they tested the valve body ( it is attached to the valve body right ? ). Only heats up when pushing, it will actually cool down while idling or shutting down machine. I reckon next step I will pull pump off and have it looked at. What about where the filter screws in? Is there some kind of bypass there?

Shucks, I should have asked for the serial number I suppose. The lower serial numbers don't have the cooler, but the higher ones do, according to the manuals. 159987+ would be the higher ones.

Did you get the pump off, by chance?

 

[mestizo]

Whats the serial number of your machine?

Have you checked pressures stalling all of your functions? Theres a port right on the side of the valve when you open the door for checking pressure.

You should see 3100psi at full engine speed, 100F. Check this by hooking up a gauge and stalling your tilt function. If thats good, stall your blade angle left and right to check your circuit reliefs. If they're set right (7600psi), your system pressure should stay at 3100psi when stalling angle.

 

[Scott 650j]

update- took the pump off had tested it was bad- dozer running good. thanks for all the feed back