Komatsu WA430-6 hydraulic system overheating

[Oldboy]

Hello again,
we have supplied a used Komatsu loader to a job and the hydraulics are overheating.
Within one hour of putting the loader into a medium workload job, the hydraulic temperature goes to the top of the gauge and the machine goes into limp mode.
The following points are worth noting.

• The hyd oil and filter have been changed, replaced with Komatsu recommended
• The hydraulics are very strong, lifting a full bucket at idle no problem
• All the engine cooling systems are clean
• Komatsu dealer diagnosis ( remote by phone) suggest one of the pumps needs overhaul or replacing, they are planning to look at it after Easter. the machine is in quite a remote place.
• Does this diagnosis sound right, seems odd given the performance of the unit.
• 2009 year, Japanese build, with c17,000 hours, very well maintained but no history available
• Weather is warm but not really hot

Any ideas you may have are very welcome, thanks Michael.

 

[John C.]

Does the unit have a hydrostatic transmission?

 

[Oldboy]

No John it’s a torque converter/ power shift fully auto transmission.

 

[John C.]

Does this machine have the diagnostics on the monitor panel that you can access? I'd probably try to confirm the accuracy of the machine gauge with an infrared thermometer and maybe find the source of the heat before just snatching the pump out. Maybe take an oil sample as well. It certainly could be a pump but with no history I would start with the basic troubleshooting stuff.

 

[heymccall]

Are they any brake warnings during operation?
IIRC, the brake pump and hydro fan are on the same system, and there is a solenoid, under a bulletin, that prevents the fan from spinning full when requested, due to a defect in the solenoid.

On my WA270-7, the engine would heat up and it also had brake idiot lights on occasion, as well as brake and fan codes.
My recollection of the bulletin was that it also covered earlier machines.

 

[Oldboy]

Thanks Heymcccall for your suggestions. Ill certainly pass this along to site and they can check out your suggestions. I appreciate your input, cheers Michael.