I am working on a Komatsu PC240-6 excavator, it runs good on bucket but after one hour the hydraulic oil temperature reaches 85 deg. Celsius. I disassemble the pump and find it like new. I checked relief valve they are good and pressure on both pump are good 325bar. In this machine the return oil from main control valve goes to cooler then to return filter, could it be the oil cooler that is making the oil hot. The difference in temperature between top and bottom of oil cooler around 12 deg. Celsius is that normal. Is it frequent on these machine to have oil cooler problem, any help is appreciated
Well, we had the same problem of hyd. oil overheating on the same machine but the hydraulic pump was bad and we changed it and it works well.
Difference of 12 DegC between top and bottom of cooler means that the cooler is working well in my opinion. It would be unlikely that you would see more temperature difference than that. By external inspection does the cooler appear to be clean..? What hydraulic oil are you using and what sort of ambient temperature do you have where the machine is working..?
Well I removed the oil cooler and the radiator and I cleaned them from the outside, I checked also the inside of the oil cooler by using pressurised air and no sign of metal or rubber coming out of it. Anyway, the old oil that was used smell bad even before use. So I changed the oil and clean the reservoir and put CASTROL hydraulic oil 68. But maybe the rest of oil in the cylinder boom arm and bucket still having effect on the quality of the oil. The ambient temperature is around 30 degree C
We run with the same problem but with a WA320-6. If you touched the tank it was really hot. We changed all hydr fluid (even arms cylinders) and it worked fine