I was a fleet mechanic for Speedway police etc in the early 80s and we used Kendal oil. Every oil change was sampled and put in a small tube to be analyzed. I had a book with a test sheet for every vehicle.
Couldnt believe the dollars we saved. All bearings have copper in them . Our reports would include copper-bearings,water/antifreeze-leaks, chrome-piston rings, cast-camshafts etc...fuel in the oil . Saved us a ton , even sent a new ford back for warranty repairs based on two samples high in cast iron , had camshaft lobes coming apart at 10,000 miles ........
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