Combines Overheating Hydraulic Oil

Check the pressure switch controling the engagement accumulator. Bulb that sits above the stack valve has a pressure switch just below it and if charging the accumulator all the time, it will overheat the hyd oil.

You can check this by listening for a steady hiss sound when standing by the hydraulic valve stack. Unplug that switch and the hiss will stop. It should only activate for a second every few minutes if you are not engaging any of the belt drives. Ours was stuck on and it took me the whole wheat harvest to figure out what was wrong with the over heating oil. I measured the temp and it was only just over the spec. so I kept going. Imediatly after changing the switch this hydraulic pump started leaking through the housing sides. A new kit did not fix it. The oring groves were quite worn. I think the pump was over pressured and that wore out the sealing faces of the pump. So dont run it too long like that. You got to buy all the pumps they are ganged together and New Holland cant sell you just the one you need.

Thanks for the information. I am working on installing a pressure guage into the connection infront of the pressure sensor. I have found what is causing the oil to heat, when the accumulator pressure valve opens and repressurizes the accumulator it is causing the high pressure valve to blow-out, inturn heating the oil(put a temperature gun on the entire system to find this out) I am getting closer to getting it fixed. Thanks for the input. I thank you for the advice on not running it I have parked it until I figure this out.(do not want to have the same problem with the pumps.)

make sure the header is on the ground and check the oil level it must be on the red line or just under if it well over it will over heat because their is no expansion in the tank also newholland have reset the new temp senders at a higher temp to solve this problem (this is a common problem)