Sunday, July 27, 2008

Re: question about oil filter examination


I have read your knowledge base post on oil filter examination and wondered if the author (or other knowledgable person) could answer a quesion for me.
I routinely open my filters. Under casual observation nothing much is evident. The last couple of times I looked a little closer than usual and in bright sunlight. In the bright light I can see scattered microscopic shiny bits. They are so tiny you wouldn't see them other than by their reflection. I have been told that this represents an inconsequential finding, possibly microscopic bits from plating - normal wear finding. Would you agree?

I also find little bits of debri here and there, non-metallic in appearance and non-magnetic. It has the appearance of a tiny quantitiy of sand which may be just what it is.

I have not found anything large, magnetic, or otherwise scary looking.

Ultimately my question I suppose is; Should anything at all be visible on the pleats? I would imagine that filtering oil through there for 40-50 hours your gonna find something. That's what it's there for, right?


On my other web site I mention how to use sunlight to see microscopic particles in the oil। http://www। These might be small bits of bearing material.

Often with mechanics I don't agree with their theory but I do agree with their actions because often it is based on years of practical experience.

It is not normal for parts in an engine to shed metal particles. Possibly during initial break-pin (when you have surfaces getting to know one another) you can have a small amount of particles. From then on normal wear on surfaces does not generate particles. So much for theory. Now what do you do about it?

If the particles are very small and not many then typically the answer is to keep checking and make sure it doesn't get worse.

For your stuff that looks like sand. Try to squish the particles between two pieces of glass or your finger nails. Sand will not squish and will scratch the glass or your finger nail.

By examining the pleats you aren't going to find cam lobe or cam follower material in the early stages of failure. Better to rinse the pleats with solvent and a toothbrush. Drain the liquid through a coffee filter land let dry. Place a magnet under the coffee filter and move all of the iron to one side. If there is enough fuzz sticking to your magnet to cover the end of a stick magnet then inspect the cam lobe and follower. You will get a much better idea as to the amount of stuff that is in your filter using this method.
John Schwaner

Subscribe to Mechanic's Toolbox Newsletter at

No comments:

Post a Comment