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You may have already performed this test, but I want to make sure. It is a leakdown test, and it is the most accurate test to determine engine wear/oil consumption. I will tell you that according to industry standards 1 quart of oil consumed in 4000 miles is normally a very acceptable consumption rate for an engine in good condition.
Oil is used to coat the cylinder walls to protect the cylinders, pistons and rings. The thin oil residue on the cylinder walls gets direct exposure to the flames, and combustion pressures. The flames are 1200 to 1400 degrees, and the pressure can top 1000 psi. Under these conditions some of the oil film on the cylinder walls gets vaporized, and consumed. Engine oil doesn’t fare well above 375 degrees, so at this point the oil is pushed past its normal parameters, that is why some of the oil is vaporized. But the engine can't operate without this small sacrificial oil loss. This oil loss is because of the particular engine design, and oil formulation, engineers try to keep oil consumption to a minimum. Depending on the chosen motor oil, and particular engine design this is all a variable. Sometimes switching oil types can improve the consumption rate. Also higher performing engines experience this problem to a greater degree than low performance utility engines do. The higher performing engines have slightly wider clearances many times, they also have higher combustion pressures, and temperatures are more common, because of the power levels they produce. The recommended leakdown test will tell you if there is a problem. As a note the normal industry standard where problems are indicated is oil consumption over 1 quart per 1000 miles. If you have any more questions I am here to help. Good luck, and Thanks for using Just Answer.
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