"Non-detergent" multi-viscosity oils do not exist. The above comments about detergents holding contaminants in suspension is correct, but the actual reason for them is different. Detergents grab onto and hold particles TOO SMALL FOR THE FILTER TO STRAIN OUT. Those contaminants are held in suspension and dispersed by the oil so they don't form large clumps, and they get drained out with the next oil change. An engine that has run non detergent oil for a long time might require several oil changes before most of the sludge it contains is cleaned away. You can "de-sludge" an engine by adding a heavy dose of Diesel fuel to the oil for a few minutes before changing the oil, but don't drive the vehicle- - - -moderately fast idle for a while, then drain the hot oil/Diesel mix and most of the sludge will go with it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!