I have a handful of customers who take advantage of Oil Analysis for varying purposes.
It is key to have a clear goal in mind when beginning an oil analysis program – Do I want to extend my drain interval? Am I trying to find my oil drain “Cushion Zone” so I know I’m safe if we are late on an oil change? Am I doing it for preventative reasons?
Whatever your reason, when you receive the sample results, what do you do with them?Are you able to clearly understand what the results are? Do you have a specialist to help you understand them? Do you take immediate action when a sample comes back in poor condition?
After extensive training in reading analysis reports and helping my customers deal with the results, here is my crash course for you in a 3 part series!
Engine Oils
Oil analysis to me is like a puzzle. There is usually a best place to start when reading the results and I recommend pretending you have no idea what product was tested to get the best interpretation of the result.
Basic analysis typically runs around $15 per bottle and 10 bottles usually come in a “kit”. Expect to spend around $150 per kit unless otherwise determined by your provider.
There are 3 main product categories when the lab determines what test to run: Engine Oil, Hydraulic Oil, or Gear Oil (Grease is in a different5 altogether). It is common for many excavators to use engine oils as hydraulic oils and this can make the result tough to understand. When the sample is pulled and labeled as “Hydraulics” a hydraulic oil test is run on the engine oil and logic says an engine oil is not going to test well in a hydraulic test. A bunch or red flags usually come back from this but your specialist will help you to determine if they are warranted or not.
- The first thing to look at on a sample result is the viscosity.
Note on this example that the viscosity test was run at 100ºC and the result was 13.1. Products are either run at 100ºC or 40ºC and engine oils will always be run at 100ºC.
Now lets look at a viscosity chart:
13.1 at 100ºC falls into the 40w category so this is in-fact a 15w40 as it is labeled.
2. What if the viscosity and the product label don’t match?
There are a few reasons why these wouldn’t match. Maybe the tech mislabeled the sample. Usually though this is because there is a contaminant present in an amount great enough to thin down or thicken up the oil.
Here is a sample that came back with mismatching viscosity.
Notice the tech labeled it as “15w40” but the tests came back at 9.6 and 10.3 which falls into the 30w category. What could be thinning this oil out? Notice right after the viscosity result are some other results “Water” & “Soot”. Both of these are either not present or very very low so these are not the culprit. Lets scroll down to the bottom of the sample report and lookout “Fuel Dilution”. Ah Ha! Thats a HUGE fuel leak causing this oil to thin down to a 30w. Bingo.
When it is this high and for multiple oil drains in a row, you will usually see other wear metals start to appear because the oil is unable to give it’s full level of protection.
Here is another sample with no obvious contaminants:
No water, no fuel, no soot or dirt, but look at the chemistry. Sodium and Potassium are off the charts. Coolant is made up of Sodium and Potassium so here we can see a large coolant leak getting into the oil.
3. Dirt
Here is a sample showing high levels of Silicon.
The first thing that comes to mind is seal material. This is why its important to know more about the machine and it’s environment. Is it an excavator, a passenger car, or over the road semi?
In this case we have an excavator in a very dirty and dusty environment. Dirt is silicon as well. I would recommend the customer check air filters and breathers to be sure most of the dirt is being caught before entering the system. If this were a passenger car, I would be concerned with seal wear.
4. Additive Chemistry
The last area to look at on a sample report is the additive chemistry or additive package on the oil.
The elements that make up additive packages, which differ by brand and type of oil, are Boron, Magnesium, Calcium, Barium, Phosphorus, and Zinc. An engine oil will typically have high levels of Zinc, Phosphorus, and Calcium. This is usually the last place I look when trying to figure out whats going on with the oil.
Here we have a sample from a final drive using 30w engine oil and this particular piece of machinery has been sampled twice in recent history, which is why there are two columns of numbers. The first test performed is on the left and the second test on the right.
Notice the different levels of each element in the additive package. Usually the same product can swing by about 200ppm. These are WAY different. In fact, these are so different that I would suspect more than just a different brand of product was used, I would suspect that originally a gear oil was used. Gear oils have much lower levels of elements than engine oils.
If you suspect a sample may have been mislabeled, the additive package is where you can verify what type of product may have been used.
I realize this is a lot of information to digest and I do hope it helps you if you ever need to use analysis.
TLDR (Too Long Didn’t Read) – First check viscosity, second check for contaminants, third check additive chemistry, and lastly, look into wear metals.
Helpful Links:
Wear Metals Guide – http://www.jjscheckel.com/Flyers/SpectometerMetalsGuide.pdf
Viscosity Chart – 