Oil analysis–a staple of extended drain interval programs–is a marvelous tool to help you understand how an engine is wearing. The problem is, oil samples must be taken regularly and faithfully from each engine in the program. Meaningful results require care and discipline, two qualities where–admit it, buddy–you may be a few quarts low.

Another argument against a fleet-wide oil analysis program is the longer design life of today’s engines. If they’ll last 750,000 to 1 million miles, why go through the hassle of ensuring their health through analysis?

However, the benefits of oil analysis may be too good to pass up. Here are three alternatives to a fleet-wide program:

Perform oil analysis on a select number of engines within a larger group of identical engines. Results can be assumed to be representative of all the engines in that group because all are the same and see similar service.

Set up a safe but extended drain interval with the builder’s help and follow it during the first couple years of an engine’s life. Then start analyzing oil in a later
period of ownership to be sure the engines are still healthy.

Use an authorized extended interval and don’t bother with analysis–let the next owner worry about it. This makes sense in trucks carrying light loads in high-mile service, and for trucks sold or traded while still young. It wouldn’t be wise with heavy loads and hard running, or in local service, or in vocational trucks. Engine builders seldom authorize extended intervals for stop-and-go or dirty environments anyway.

Probably the best route for anyone reluctant to undertake an oil analysis program, or for a small operator who can’t get the attention of and advice from the builder, is to use regular published intervals and forget extended drains.