HI First post ever. I am having issues with our wa380. Is overheating the hydraulic oil very easily after about an hour of run time. I did my first checks and changed hydraulic filter, Checked strainer, and Pressure washed the cooler out real good. I also checked fan speed and pressure, it checked out in spec. I hooked up pressure guage to main control valve assembly to check main pump pressure and function. System pressure check out good to relief.. So while running and going through functions all of the sudden noticed that the main pump would not destroke and you can hear going through one of the relief valves. (Which i think is my overheat problem). If I then manually send a fuction to main system relief it clears and returns to normal. But as the hydraulics get warmer it happens sooner and sooner. I pulled the main relief and found no damage. Both springs in one piece. PPC pressure is in spec. This machine has about 12k hours on it.
Shermanh, is you WA380 a -5, -6, -7, -8? Serial number would be handy as well.
This is a -6. SER number is A53046
Sorry that serial number is A53065
Believe the key element you uncovered in your testing is the fact that you have noticed pressure in the work equipment system with out moving a work equipment function. This hydraulic system is what Komatsu calls CLSS (Closed center Load Sensing System) where the load sense pressure generated at the work equipment spool (based on load on work equipment cylinder) is taken back to hydraulic pump to act on work equipment pump servo to increase pump displacement. Have seen where a sticking servo spool will hold pump "in stroke" without moving a work equipment function, leading to the hydraulics overheating as you have described.
That seems to be the direction I was headed for. It doesnt matter which function I use, weather bucket or boom it will stay stroked up. And it does this real quick and fast the warmer the oil is. I will update after more testing and a solution is figured out. Thank you for your reply.
Did you ever find anything on this?
I am having to have another company look at this. Im stumped. I had the local Komatsu dealer come out and they made a suggestion but didnt know for sure.. The tech suggested a new unloader valve. I replaced that and it did not cure the problem. Meanwhile after getting a $3200 bill Im done with them. Pretty pissed they said they would send the tech out again and after a month and not returning my phone calls I have decided to go another direction.. I just transported the machine in and will report after the other companies findings.
Hi there Does anyone have a solution to this problem? We have the exact same problem with our 380-6 with a close serial # as well. It appears this may be a common problem with these units.
I am still having issues with this unit. I had to break off to deal with a hst pump on one of my wa320 loaders. Did you figure anything out with your unit. I have found with testing that after I have warmed it up good and the fault occurs consistant it seems to happen with both circuits. The lift and the bucket. Was wondering maybe pressure compensation valve but i cant tie it to either valve section when it occurs. One thing i do notice is when i barely move the bucket actuator the system pressure spikes more to get the the bucket moving then comes down to working pressure to operate. When i do the same with the boom I dont see that spike and it just comes up to the pressure needed to raise the boom.
I did replace the servo valve on the main pump thinking possible sticky valve but condition has not improved.
Hi there Yes, we did find out these models have a bad designed implement and steering pumps. There is a factory update we found from 2008 that was put out. Our steering pump is still holding together for now. We replaced the implement pump that runs the boom and bucket. What happens, is it gets slightly worn and makes the swash plate stay open. The updated pump requires the updated hardware to install. It was around 8k with our mechanic doing the work in house. It looked like a pain, he had the cab off to do this repair. I’ll link update and pic of our machine being worked on. It seems that it fixed the problem. We only have a few hours on it since the repair though. Fingers crossed. The update won’t let me send the file. If you have an e-mail address I can send it to you in pdf form.
WOW thank you for that info. Seems more than likely this is my problem. I was trying to steer away from my pump but something in my gut was telling me pump. Really irritates me that the Komatsu tech didnt dig this up when i had them out to troubleshoot my machine. Here is my email if you could send me the full file. Much appreciated. I'm going to have a war zone around my shop. Have to cab of my 320 waiting on pumps for that machine already. [email protected]
Update on this machine. I've had this machine out working now for a month working full shifts on a pipe crew. Working great. Thanks to Khuff for the info. I replace the pump with a reman which is updated to the right spec. Was very frustrated with the dealer that came out in the first place and pretty much stole my money and never returned. Then double billed me on top of that.
Thanks to Khuff and shemanh for sharing the final solution to these Komatsu wheel loader hydraulic overheats. Stuck swash plate will heat it up exactly like you said. Been waiting for the solution to this problem, in my archives now. Simon C