Drain Plug Magnet Analysis using 60X microscope.
Engine is VW 1.8T with 87K miles on it. Oil was approximately 80% Mobil 1 0W-40 mixed with approx. 20% Mobil 1 5W-40 TDT. OCI of 3900 miles.
Most of what's seen under the microscope is way too small to show up as distinct particles. It just looks black with both naked eye and under 60X microscope. Most of the occasionally seen shiny ferrous wear particles are about 8 microns in size...barely if at all detectable with standard UOA wear metal analysis. One particle I saw was about 28 microns in size which would not be detected by UOA.
I have wondered for the last few years I've been doing this what the black debris is made of and what size the particles are. They are certainly small enough to be accurately picked up by UOA, if they are made of element(s) that are being measured. I can't rule out it being soot that somehow gets stuck to the magnet; could be agglomeration due to static charge attraction, or due to pure magnetic attraction. Perhaps I will take the magnet whiping to the super microscope that's in another building at my work. That may shed some light on the black stuff.
I did not change the oil filter so this time I did not get to analyze the magnet debris from the magnet that goes inside the oil filter or the Filter Mag that goes on the outside of the filter. They catch a lot more debris than the drain plug magnet.
Magnet analysis is fun, inexpensive (assuming you have a microscope), and interesting. I recommend it to others.
Engine is VW 1.8T with 87K miles on it. Oil was approximately 80% Mobil 1 0W-40 mixed with approx. 20% Mobil 1 5W-40 TDT. OCI of 3900 miles.
Most of what's seen under the microscope is way too small to show up as distinct particles. It just looks black with both naked eye and under 60X microscope. Most of the occasionally seen shiny ferrous wear particles are about 8 microns in size...barely if at all detectable with standard UOA wear metal analysis. One particle I saw was about 28 microns in size which would not be detected by UOA.
I have wondered for the last few years I've been doing this what the black debris is made of and what size the particles are. They are certainly small enough to be accurately picked up by UOA, if they are made of element(s) that are being measured. I can't rule out it being soot that somehow gets stuck to the magnet; could be agglomeration due to static charge attraction, or due to pure magnetic attraction. Perhaps I will take the magnet whiping to the super microscope that's in another building at my work. That may shed some light on the black stuff.
I did not change the oil filter so this time I did not get to analyze the magnet debris from the magnet that goes inside the oil filter or the Filter Mag that goes on the outside of the filter. They catch a lot more debris than the drain plug magnet.
Magnet analysis is fun, inexpensive (assuming you have a microscope), and interesting. I recommend it to others.
