Reliability's Dirty Little Secret

Jim Fitch, Noria Corporation
Tags: industrial lubricants

I’ve told this story to nearly every one of my seminar audiences in the past five years. For me, it was one of those defining moments that gave me surprising insight on where we are in our journey to lubrication excellence.

By the time you can see or feel dirt in the oil, much damage to your machine has already been done.

I received a phone call from a stranger who introduced himself as a maintenance manager of a large steel mill. He told me he was preparing to teach a group of lube techs about how and when to perform an oil change on mill machinery. However, he first wanted my advice. I agreed, expecting one of the usual questions, such as whether they should switch to a synthetic or if a flush was needed. Instead, I was startled by a question I’d never heard before … and never expected to hear.

He asked, “What should the oil feel like between your fingers when it’s too dirty and in need of a change?” He said he wanted his lube techs to change the oil based on feel. At first I thought it was a prank call; you know, from a friend looking for a good laugh. I listened intently but stayed quiet, studying the caller’s voice. He kept talking. Soon, however, I realized this guy was for real.

My reply to him was measured and regrettably a little rude. I told him that perhaps before he taught anything to anybody about lubrication, he should get into a class himself. I explained to him the microscopic size of clearance-sized particles and how they compare in dimension to the ridges in your fingerprint. I mentioned that by the time you can see or feel dirt in the oil, much damage to your machine has already been done.

Then I offered him a generous discount to attend one of Noria’s seminars. The call ended and I haven’t heard from him since. For the next couple of days, I kept thinking about the larger message behind his question. What had I learned from talking to him? Was it possible that there was such general misconception in the maintenance community about the No. 1 cause of wear (invisible small particles)? Did his question reflect an unspoken general belief about particles being harmless if they can’t be seen or felt?

As I said, this was no small revelation for me. It reminded me of the philosophical question: if a tree falls in the woods, does it make a sound if nobody is there to hear it? If you cannot see or feel particles, are they there? Do they impart harm?

Despite the fact that most people who work around machinery have never seen the likeness of a virus or bacteria, many share the belief that similarly small particles in oils and greases are generally benign - out of sight and out of mind. This can be widely observed simply by the way lubricants are routinely stored and handled. Today’s reality check is that small particles indeed pack a wallop in terms of machine reliability and life expectancy. The widely held belief that small particles are not harmful sadly remains reliability’s dirty little secret.


About the Author

Jim Fitch, a founder and CEO of Noria Corporation, has a wealth of experience in lubrication, oil analysis, and machinery failure investigations. He has advised hundreds of companies on developing their lubrication and oil analysis programs. Contact Jim at

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