No Longer A 'Generic' Service; Variety of Blends
Required To Meet Today's Engine Requirements

Years ago, an import shop could consider its shelves well-stocked if it contained a selection of single-viscosity oils in detergent or non-detergent blends. Today, a shop owner is confronted with stocking a variety of multi-viscosity oils, including 0w-20, 0w-40, 5w-20, 5w-30, 10w-30, 10w-40, 15w-40 and 20w-50, not to mention stocking some of these viscosities in synthetic and non-synthetic bases. Although the number of oil viscosities currently available is bewildering, it's also important to remember that the most important factor in selecting motor oil for specific applications is the quality of the oil's base stock and its particular blend of additives.

With that in mind, it's also important to remember that motor oil must efficiently perform at least six different jobs in the engine's crankcase. It must, for example: 1) reduce friction between moving parts, 2) seal piston rings against the cylinder wall, 3) cool pistons and engine bearings, 4) cushion bearings against shock loading, 5) clean sludge and varnish from engine parts, and 6) prevent corrosion while an engine is parked or in storage. In addition, application-specific oils might, for example, be formulated to prevent piston rings from sticking or the camshaft from scuffing in particular applications.

MODERN ENGINE LUBRICATION
Before we begin to understa...