Engine oil analysis is an underutilized diagnostic and marketing tool for service-oriented tire dealers. The automotive equivalent of a blood test, oil analysis is practical, affordable and extremely accurate. In my last column, I described how aggressive service shops build customer loyalty and confidence by evaluating used cars prior to purchase. Along with a used-car inspection program, a progressive owner can market two big benefits of oil analysis.
First, it gives potential buyers invaluable insight into the actual condition of vehicles they may buy.
Second, and equally important, oil analysis is an impartial, scientific evaluation that boosts the professional credibility and image of service personnel who rely on it.
The procedure's a far cry from the tire-kicking, ``by gosh, by golly,'' methods people often used to judge an engine's condition. It can prevent a well-intentioned dealer from OKing a vehicle that's a major breakdown waiting to happen.
I speak from experience, since I've been using oil analysis on family cars since 1978.
A lubricant supplier should know where an oil analysis laboratory is. Major oil manufacturers usually refer customers to one or two independent oil labs they've found to be reliable and reputable.
An oil sample kit, which contains a several-ounce sample bottle, identification label and pre- addressed mailer box, currently costs about $12-$15. Some labs only sell sample kits 10 to a box, but buying 10 lowers the unit cost.
Thoroughly warm up the engine then remove the drain plug, allow oil to drain out for just a moment and catch several ounces in the sample bottle. Then cap the bottle, wipe it clean, fill out the required information on the identification sheet and bottle label, and it's ready to mail.
The labs I've used over the years usually have a printout of test results and recommendations in my hands within five working days. When I request it, the lab sends me the report via facsimile as soon as an analysis is completed.
I have not only used oil analysis to help diagnose problem engines, but also to help family and friends assess the condition of used vehicles they wanted to buy.
The most meaningful oil analysis data comes from a vehicle on which oil has been sampled on a regular basis. However, one sample from a problem vehicle or used car is still valuable because experienced lab technicians compare results to those of known-good, well-maintained engines.
When you drain the crankcase, what you see is what you get. Changing oil immediately before the sample is taken would skew the test, but darned few people change oil prior to selling a vehicle. What's more, they needn't know that your whole-vehicle inspection includes an oil analysis.
For example, abnormally high concentrations of iron contaminants suggest worn cylinder walls and/or piston rings. Excessive chromium deposits also may point to worn rings. Aluminum deposits usually result from piston and bearing wear. Worn bearings also increase the amount of copper and lead found in engine oil. However, lead contamination may confirm the vehicle was improperly fueled.
Abnormally high levels of tin also suggest bearing and piston wear. Excessive silicon usually confirms that airborne dirt is entering the engine. This points to a poorly sealed, improperly installed air filter or filter housing.
Combinations of boron, sodium and potassium flag an internal coolant leak because these chemicals are additives found only in the coolant. My experience has been that oil analysis will detect coolant contamination long before you find the familiar milky residue in the oil or the driver notices a loss of coolant.
Bi-metal engines (aluminum head/iron block), which are commonplace today, make early coolant leak detection vitally important. That's because these engines are prone to head gasket and coolant leaks when overheated. Worse yet, the damaged area may seep coolant for some time before any symptoms of trouble are noticed.
Oil analysis builds customer confidence and peace of mind by identifying these internal problems long before catastrophic, potentially embarrassing failures occur.
Lastly, oil analysis data may help settle disputes over premature engine failures. Tire dealers with fleet accounts can use periodic oil lab reports to monitor the ``health'' of an entire vehicle fleet.