Cat 325CL sn 0325CHBFE00917. Hydraulic oil temps rise after about an hour of starting work causing derate. Engine temps stay mid-range. After oil temps rise, idle few minutes go down but rise again quickly when working. Hydraulically driven oil cooler fan doesn't speed up with engine rpm increase as it should. Probable cause? Thanks
First, retrieve stored fault codes and stored event codes from the monitor. Record and share all of them. Quick and dirty test on fan performance is to unplug the electric going to it. This will place the fan in full ON. The downside is increased fuel consumption and noise. If the as built fan assembly has the wiring coming out of the engine block side, that style is now obsolete. All replacements have the wire coming out of the hub center on the radiator side. Note, that fan clutch is $$$$. Back to issue at hand, on my 328DLCR machine require steam cleaning of the cooler/ radiator every 3 years, regardless of being able to see light through them.
Scratch that fan wiring. Original was wired on hub side toward radiator. Update is wired from engine side to outside radiator fan guard.