Tech Stuff

Oil change intervals revisited

There has been quite a bit of discussion among both the public and within the industry regarding engine oil change intervals. My opinion is that any engine’s oil and oil filter should be changed at a frequency of about 3,000 to 5,000 miles.

There are those who claim that recommending oil and filter service at this range is a ploy among service shops motivated strictly by the desire to increase shop income, as though it were some type of conspiracy to scam the motoring public. Have those pessimists heard of the phrase “penny wise and pound foolish”?

Again, in my opinion, spending a few more dollars for every 3,000 or so miles driven is a small price to pay for ensuring that the engine remains clean and functional. And, no, I don’t care if the oil being used is fossil-based, a synthetic blend, full synthetic or derived from the planet Krypton and refined by the gods of interplanetary chemistry. I want my engine’s oil circuit to remain clean, maintaining adequate oil pressure and delivering clean lubrication to main bearings, rod bearings, wrist pins and valvetrain components.

Yes, oils do exist that feature improved chemistry that in theory will provide proper lubrication for far-extended periods. But the reality is that variables exist to potentially negate the benefits of extended oil change intervals.

These variables include such examples as coolant seeping into the oil circuit due to cylinder head or block porosity, a leaking cylinder head gasket (likely due to a cracked head, improper head installation or as a result of engine overheating), fuel contamination due to leaking injectors or an overly rich fuel system, debris contamination due to an open/faulty air intake system, etc.

The fact is that in the real world, all engines do not function in textbook-perfect conditions, and oil contamination is certainly possible.

The cost of replacing an OEM engine with a new OEM engine can run anywhere in the $5,000 to $30,000 range, depending on the specific vehicle. Add to that the cost of shop labor. Rebuilding a production engine can easily run anywhere from about $3,000 to $15,000 or more.

More frequent oil changes will dramatically reduce the chance of dealing with a sludge-monkey like this ill-maintained GM 5.3L.
<p>More frequent oil changes will dramatically reduce the chance of dealing with a sludge-monkey like this ill-maintained GM 5.3L.</p>

My point is simple: Spending $20 to as much as $200 or more (again, depending on the application) is a small price to pay to avoid the prospect of a much more costly engine repair or replacement.

I like engines. Actually, I love engines. Whether they’re operated at 2,000 rpm for short distances or run at 6,000 rpm and pounded-on brutally, they live a tough life, and we expect them to perform as designed. Why not treat them with the respect they deserve and at least keep the innards clean? The moral: More frequent oil changes equals increased insurance against potential damage.

I want to make one thing very clear: Today’s oil manufacturers offer wonderful products, including “higher mileage” blends and full synthetics that perform outstandingly, with excellent lubrication, cleansing and longevity, and I am certainly not about to criticize those products. My point deals with real-world intervals with often imperfect engine conditions, and in no way is a criticism of the ability of these oils to perform. It’s simply my opinion that I would rather spend more money by changing the engine oil in my vehicles on a more frequent basis in an effort to keep them clean and to attempt to avoid lubrication problems in the long run.   ●


What’s your outlook, based on your experience, with regard to oil change frequency? Do you follow OE recommendations, do you recommend intervals based on your own experience and opinion, do you prefer a specific type of oil for certain applications? Do you have horror stories based on what you’ve seen in the course of your work? We want to hear from you. Once we have enough replies, we’ll publish an article that opens a discussion regarding our readers’ thoughts on the matter. Leave your comments here or send them to: mike.mavrigian@bobit.com

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