Machine is only four years old with 2000 hours. I bought it recently and have already had to install a turbo and actuator, probably because it sat for about a year in New Mexico after it came off JD lease. Last Thursday it started overheating and giving a low fan speed code. Took it to dealer and they found black rubber bits in the fan drive motor proportional valve, which they cleaned and reinstalled. I told them to go ahead and drain the tank and I would bring 50 gallons of zinc free oil and I wanted to look in the tank. Tank was clean but they hadn’t pulled the filter (which I had recently changed at the 2000 hour service). I had them remove the filter and cut it open. Not much rubber in the filter, but I found these large chunks in the filter housing. Dealer didn’t know what to do, so I’ve brought it back and studied on it for a couple days. The source of contamination surely must be a return hose, because these large chunks didn’t go through a pump or a valve or the cooler in my opinion. Today I started removing return hoses and looking through them with a flashlight. No luck yet, but tomorrow I’ll remove that big hose from the bottom of the cooler to the tank return inlet. Anybody got any other ideas?
That definitely looks like the inside of a hose.
Removed the large hose and inspected it with a borescope. It is intact. And in fact it has a slight spiral pattern inside, as did the other two return hoses I could see through. The chunk I found in the filter housing is very smooth on the inside surface, so I’m still wondering if I’m approaching the problem correctly. Perhaps it is not a piece of hose? But what else could it be? And how did it get there?
Zoomed in the second pic sure looks like wire impressions. From a pressure hose.
I don’t disagree, but would a pressure line have a large enough path back to the tank? There is a return pipe coming from the bottom of the main valve bank. Could this chunk come through that valve body? There were two chunks about equal in size, and a spoonful of small pieces in the filter housing bottom. Here’s a better closeup photo.
Try again with photo.
That could be from a previous hose failure as well. I’ve pulled lots of pieces like that out of tanks over the years. I’d check again after a bit of running.
Good idea. Dealer mechanic showed me the location of the fan drive proportional valve, which is different from my 350D. I can keep removing and cleaning it if it slows the fan again until the issue finally resolves itself, either by frequent cleaning or the eventual failure of the offending hose. I’m going to put the machine back to work with instructions to watch the temperature carefully.
Another late-night thought I had is to install a field- modification filter in the fan pump drive hydraulic circuit. The way this fan drive works is that it has its own engine driven pump not connected to the main machine pumps at all. This separate circuit draws oil from the bottom of the main tank, sends it to the proportional valve and fan drive motor, then returns it to the tank. If I could install a filter in that circuit without restricting the flow to the fan drive motor, it might save some headaches. But I don’t know how to calculate what filter would work for this modification, and I don’t know whether it would need to be installed on the suction side or the discharge side of the pump circuit. I do know that there is a lot more free space on the suction side. Any of you flow rate engineers know how to do this?
Does it have auxiliary lines on it? Possibly had an attachment of some sort in it's previous life that had issues.
Is it possible that John Deere would have service / warranty records on the machine ?
Excavator was used mostly as a hammer machine, which is one reason it had fewer hours than all the others in the lease return group. I’m pretty sure the dealer in New Mexico looked up the service records when I bought it because it seems like there was one item showing but I don’t recall what it was. I’ll have my current dealer check it again.
Do you know the displacement of the pump and maximum RPM?
I surely hope you can get to the bottom of this. Engine or hydraulic overheat is NOT an option. That said, I gotta say this- I aint been everywhere, but I have NEVER seen a hose fail internally without obvious evidence externally.
This may be the key. I'll look it over good. And it very well may be the remnants of a previous hose failure. We are hauling it back to the site this morning to put it back to work today. I should know more after a few hours of running. If it happens again, I may research the "add-a-filter-in-the-fan-drive-circuit" idea some more. Lots of good ideas on this forum from guys with experience.
I had a rubber hunt on a dozer. Found chunks in filter and cooler. Removed every hose in circuit, zip wheeled open lengthwise and inspected, never found it. We wondered if a hydraulic cap seal fell in and somehow wound up in charge pump and got chopped up. Never found the source, ended up putting machine back together with new hoses and sending her out.
Machine has worked fine all week with no issues. Hopefully we got all the rubber bits out of the system.
Thanks for the update. Oil and filters are really cheap compared to pumps and downtime.
Have any hoses that look newer then the rest?