Any one now what the normal operating temp sould be
Rule of thumb I have always been told 100* fareinheit above ambient
Mine was you should be able to lay your hand on the tank but not for long about 70 -80 /deg c
Well mine is running 80 to 85 depending what I'm doing and thats on a hot day 30 degrees but she really slows down after she gets into the 70's
I don't deal well with the centigrade scale but it shouldn't run much past 180 degrees F on a hot day. It would unusual to have you hydraulic oil run hot and not your engine temperature. In my experience the space between the radiator and hydraulic oil cooler fills full of junk and shuts off the air. I have seen a couple of times where the pumps got sloppy and loose and made things hot. Since you mention the machine slowing down there's a better than even chance of some tired iron. You didn't mention how old and how many hours you have on that monster. There is also a function in the computer that cuts back on horsepower when the engine temperature gets above 205F. When you see a machine that had been running hot you will see lots of bleeding hoses and leaking cylinder rod packing.
What oil do you have in the beast? Might want to follow John C advice and check on the oil cooler set up,but if you are getting that type of heat and loosing power you may have a issue with your pumps but there are more qualified people here than me for that diagnosis.
Make sure the sides and top have all the insulating foam in place. If not it will pull air around instead of through the radiator. Pull the suction screen in the hydraulic tank and look at it. It would also not hurt to cut open the hydraulic filter. If the engine speed is staying up my guess there is something wrong in the load sense circuit. What ever tells the pump to stroke more. It is probably a weak relief.
Please let me know the Delta T, in and out for hydraulic oil cooler for this machine or equivalent, fomula.. Many thanks,
I usually look for about 20 degree F. between the in and out measured with an infrared thermometer on the pipes.
Thank you very much for your information, but could you tell me max, min range ? Thanks and best regards, M THANG
I don't know of a specific max oil temperature. I suspect that would be set by the oil company. Usually when I have a machine with heating problems I see a five to ten degree Delta T. It also depends on the ambient temperature. If you are in a hot climate working an excavator very hard I suspect you could overwhelm the coolers. I have seen it happen in the logging industry where reversible fans are becoming normal. Any dirt in the fins can make the machine run hot.