By Jim Fitch
Book Chapter. Automotive Lubricants and Testing. Edited by George Totten and Simon Tung
Most oil analysis performed in North America is done on diesel engine crankcase oils, primarily for large fleets in the transportation and off-road equipment industries. Ranking second would be the analysis of lubricants used in stationary industrial machinery including compressors, turbines, gearing, bearing lubes, and hydraulics. Far down the list is engine oil analysis performed on crankcase lubes from automotive fleets or privately owned cars and trucks.
Although there are a few isolated exceptions, condition monitoring of passenger car motor oils (PCMOs) has not yet emerged as a strong market. There are several understandable reasons for this. One is the fact that most car owners are not interested in paying a premium to extend engine life. Most car owners seem to be satisfied with the current engine life expectancy. This is evidenced by the fact that less than 10 % of PCMOs in use are synthetic formulations despite their widely promoted benefits.
Unlike commercial and industrial applications, in which machine owners often run equipment to their end of useful life, car owners are more commonly enticed to sell earlier for newer models. After all, why invest in engine life extension when the benefit of the investment would only be gained by the next owner of the vehicle?
Sampling is another impediment. Automobiles are not fitted with convenient oil sampling valves, nor are these valves easy to retrofit on engines. The only practical alternative is to obtain a sample from the dipstick port by drop-tube vacuum sampling or from the oil pan drain port. Neither of these locations is suitable for obtaining a representative sample.
The other factor is the cost and turnaround time of getting the data. Although laboratory automation has increasingly enabled basic tests to be performed quickly and with minimal cost of labor, routine oil analysis is still expensive for personal car owners. Some instruments are actually an integration of several conventional oil analysis sensors and often include viscometry, molecular spectroscopy, and atomic spectroscopy, typically with no needed glassware or sample preparation steps. So too, many new onboard sensors have been introduced that monitor key oil properties in real time. They displace the need for oil sampling and can alert the car owner to the optimal timing of an oil change or the presence of aberrant oil properties and wear metals.