Don’t put in a quart over and run the engine -My engine retains about 1.5 quarts of old oil when doing a change. That's a pretty big percentage in relation to the total capacity. I'd like to get more of the old oil out when making a change.
My thought was to add some extra, clean oil to the engine just before making the change. I have a quart of M1 that I won't be using in this engine, so I thought of adding it to the crankcase prior to making the change, running the engine a short distance (from home to the shop that's doing the work, just a few miles) and then draining the engine.
Would that dilute the oil so that there's less old oil remaining in the crankcase, and give me more fresh oil, by percentage, when doing the change? Thoughts?
If this bugs you enough - pour a quart through with the plug out after the dirty oil is drained.
Many folks here change oil at 5K with the same oil good for 10K … so matters little at all