hi guys, We have a Komatsu PC70FR-1 excavator with just over 3000hrs on it (bought used a few months ago). Basically as soon as we put it took work it overheated and boiled over in about 20-30mins. The hydraulics were dead slow as well. So took apart the pump (which is pretty simple but at the same time uses a much different integrated pilot pump) and found an O-ring had failed which was causing the pilot pressure to go no higher than 20bar. So we replaced the O-ring and straight away the boiling issue went away and the temp stayed at about just ove rth quarter mark on the gauge. The hydraulics were quick as well and pilot pressure was around 35bar. Well now the problem is that the machine works fine, and the heat gauge stays solid just ove quarter and the engines is not overheating etc, but the hydraulic oil gets so hot you can't even touch any of the cylinders after a couple of hrs. We've checked the coolers and radiators and all is fine there. Any suggestions guys why the oil is getting so hot?
We had a 35 and the cooler bypass was bad ,,or so the dealer said, they fixed it and all was well. Also make sure any foam or baffling is in place so the air gets pulled thru the cooler as well as the rad.
hey thanks for that man, i was just reading up on that and i think all points towards that bypass valve. gotta find it now! thanks again
Hey Typ4, i found a valve like thing thats on the hose going from the control valve directly to the tank. Is this the bypass valve?
hey guys, i shut the hose going to the tank directly from the control valve and still same issue. Any help would be awesome guys, really stuck on this problem!