Hello all: New to the forum and first post. I'm a novice and looking for a small D4 dozer to purchase for ranch work. Roadwork, clearing fence lines, pushing brush piles etc.. Can you please shed some light on the oil sample results and what should a buyer be concerned about. Specifically the different metals present and levels? How do the hours on the machine coincide with "normal" metal levels present in a sample? Been looking at Cat d4k2 xl and cat d5k2 xl's. Thanks All Todd
Most generally the lab that does the sample will explain what all the various levels mean. Not only will you potentially see metals but could also see high numbers which could indicate dust getting past air filters, coolant or fuel in the oil etc. One thing to consider is one set of random samples won't tell you much unless there's been a major issue recently. A history of consistent samples is what you really want. Hours vs. sample indicated metals will be like anything else, how often was it serviced, conditions it ran in etc. If you buy a machine, keep up the samples as you run it. To me it's especially important in compartments that run a long service interval such as hydraulic, anti-freeze etc as it could be several years before you'd potentially need to change it. It could very well catch an issue before it's catastrophic. While the indication of a particular metal being high won't lead you to exact location it will help narrow it down. It's becomes an art reading them. Your local dealer will have kits as well as most large oil suppliers. Go ahead and get one of the little pumps so you can suck a clean sample out of each compartment. Do so after warming machine up to temp so everything is mixed consistent and things haven't settled thus giving a false reading based on where sample was extracted.
The common materials that bring concern are lead, copper, iron and silica. Antifreeze in the engine oil is also and instant deal killer for me. The number and size of particles seen in the transmission and hydraulic oil is as much of a concern as what metals are shown. Final drive oils are almost always high in iron and in my experience usually a sign the oil hasn't been changed on schedule more than a sign something is coming apart. As Junkyard stated above, the oil lab running the tests will inform you what is at alarm levels and what you should do about it. The other issue is that if the oils have just been changed you are basically wasting your money by taking samples.
Ideally you have the test results going back to new, how likely is that? Next best would be to at least know how many hours are on the oil. Hopefully it's near the service interval, but even if it's new, the test might tell you if something is terribly wrong because the old oil usually doesn't get completely drained. The hours on the oil are what the levels are judged on. Unless the oil's new, then you're looking at traces of wear. I haven't read anything that would suggest the levels would change for oil with x hours on it from 1,000 hours vs 4,000 hours. I'd guess that it shouldn't make much difference from 500 through 7,000 hours on a machine that size, given consistent service. In reality, the new machines get better service, work more hours per year, and the high hour ones get used less hours per year and neglected. Last time I bought a CAT SOS kit some years ago, it was barely a hundred bucks for a pack of ten prepaid bottles and the tubing if you have the pump. If you use CAT and enter the serial number, i believe they will include any previous tests they have of that compartment?
Thanks. This is very helpful. So are samples supposed to me taken before each oil change? I took a look at a near new machine with less than 200 hours. Asked for an oil sample report and was shocked with the high concentrations for a newer machine. Come to find out after getting in touch with the service rep at the dealer that it was a victim of someone adding DEF in the hydralylic fluid and running it a bit before figuring out what has been done. Long story short they drain it a few times and filetered but metals were still high. I walked from that one. Still looking. So am I hearing you all wouldn't be too concerned about the oil samples for under 1000 hour machines? I think the error mentioned above was an anomaly but wondering how common a mistake this is? Thank you
The problem with putting DEF in the wrong tank is more common than one would imagine. A good friend of mine started making these and is now selling them to all kinds of companies. http://www.defbooty.com
No, I mentioned 500 or 1,000 hours as the point where the results would level off until it approaches failure. The first oil change will be unusually high in some metals, they should stabilize quickly with a new machine. I wouldn't be too worried about a DEF contaminated hydraulic system on a dozer (assuming it's not shared), an excavator would be more concerning. You have to remember what you're looking at. Say a 5,000 hour dozer has near alert level results for iron and silicon(dirt) in the hydraulics, and the oil has been in there way too long. Not that big a deal if you're planning to put 100 hours a year on the machine, if it works now then change the oil and it should do fine. An excavator has a much more demanding hydraulic system, you don't want to replace the WHOLE hydraulic system on an excavator, think about it. Samples can be taken at every oil change, or taken and then used to decide when to change the oil, or when to schedule rebuilds.
K series dozers are as complicated as any excavator. If you trash a hydraulic system on one you have pretty close to a total loss of the machine.
Ok. So I'm working on another machine with just under 1000 hours. Showing elevated silicon and aluminum. Silicon possible dirt in the hydraulics. How about aluminum? Am I over analyzing this aspect of a purchase on a young machine? Much appreciated
Sometimes with low hours certain levels can be higher during break in. As was mentioned the lab readout lets you know if there's any cause for concern.
If a sample comes back highly elevated in silicon I would re-test before jumping to conclusions. Its easy for a careless person to dump some dirt into the oil sample.
If I recall the Kubota in my skid steer had higher levels of copper(?) the at the first sample but was normal a couple samples later.