How to Do an Engine Oil Analysis

You have two options for analyzing your motor oil with a kit. You can buy one that lets you interpret the results for yourself, or you can purchase the services of a professional laboratory, such as Blackstone Labs or Oil Analyzers, Inc., just two of the leading firms out of many that offer oil analysis.

Either way, kits typically cost less than $30, and sampling your oil is relatively easy. Or at least, it can be. There's the somewhat messy sampling method, of removing the oil filter and catching a sample of oil (enough to fill the small container for the kit). Or you can do it the no-mess way: use a vacuum pump to siphon oil from the dipstick tube or crankcase filler hole. Such pumps are available at auto supply stores, or often, from the providers of the analysis kits.

So what's actually in the kit? If it's one that you mail in, it will likely include a small jar or bottle for the sample, along with a label you fill out that tells the lab about the sample. It may also include a separate container into which you can pack the sample for mailing. You then receive the results by mail, e-mail or phone, typically within a few days.

For tests that let you read the results at home, (like QMI of Missouri's MotorAnalyzer), you just place a drop of warm motor oil on the supplied test sheets. Then you compare the pattern produced by the oil drop with the patterns shown on the included test analysis guide. The pattern of colored concentric rings gives you insights as to:

If you're a novice, especially, it can be pretty intimidating trying to interpret what those results mean. Click to the next page to learn more about interpreting the results of an engine oil analysis.

So just what, exactly, will all this information about your engine's oil tell you? And what will that do for you?

If you send your oil sample to a lab for analysis, technicians will check for lots of things, including the presence of metals and other elements, such as aluminum, chromium, iron, copper, lead, calcium and more. If certain materials are abnormally high in your oil, it could point to excessive wear in a certain engine part.

The analysis also lets you know the oil's viscosity, compared to what it should be. The Total Base Number (TBN), which lets you know how much of the additives -- chemicals that enhance the oil's effectiveness -- remain.

Having this knowledge beforehand could save you lots of money and aggravation, as it gives you time to catch problems before they result in a catastrophic failure on your vehicle (like an engine seizing up).

The results also let you know if the oil is excessively contaminated with fuel, water or antifreeze, all of which reduce the oil's ability to lubricate your engine effectively.

But there are at least two more ways an engine oil analysis can save you money.

If you're considering buying a used vehicle, a car, a truck, a motorcycle or even a piece of diesel construction equipment can be quickly given the oil analysis test to see what kind of shape they're really in, beneath their flawlessly washed and waxed exteriors. An engine oil analysis can give you a look deep inside the workings of the engine without you having to take it apart. Naturally, a lab report that comes back showing lots of metal particles may be a sign that you should avoid taking that vehicle home.

Another potential money saver is if the analysis shows you can extend the interval between your oil changes. The recommendation used to be that you change your oil every 3,000 miles (4,828 kilometers), no exceptions, if you wanted your car to last. But on modern vehicles, the interval between changes can be 10,000 miles (16,093 kilometers) or even longer. That represents big savings of time and money, not to mention giving a break to the environment by not having to produce and then dispose of those additional quarts of oil.

For more information about engine oil analysis, be sure to follow the links on the next page.