In the old days about 15 years ago when Bobcat went to a 40 gpm machine and didn't upgrade the hydraulics and cooling system, the machines overheated in 20 minutes. It was a short lived experiment.
It sounds to me like there is a stricture in the hydraulic system or in the cooling system. A plugged radiator may not be visible from the top side.. could be plugged down deep or the coolant could have broken down and/or debris could be blocking it.
An inadequate cooling fan could also be the culprit. If the cooling fan is temp controlled or isn't spinning at enough RPM's, that can do it too. CAT C series machines had a variable speed fan and some were shipped from the factory at too low of a speed to handle high flow.
I would also check to make sure your machine is actually getting into high flow. Check coolant levels, filter, charge filter, etc. Broken down hydraulic oil and water in the system can cause issues as well as air.
Usually, though, it points to the cooling system but at the same time, a restriction in a hydraulic fitting can cause excessive heat but if it's the engine overheating and not the hydraulic oil, then it is probably a cooling issue whether it's a motor problem (head gasket) or just broken down cooling system or something simple like a fan not spinning at optimum rpm.
In the old days on Bobcat, a belt and engine rpm turned the fan. Now they kick on with heat. Is the ASV belt or hydraulic drive fan?
