Engine oil weight. 20w50 vs "dry" start up wear??? Advice to run lighter weights to minimize start up wear seems contrary to need to use lower weights in very cold conditions because of "drag" of heavier weight oil in the engine.

PO for 173k '89 5255s was running something that burned a quart per 750 miles. Switched to Shell 20/50 and got 29.4 mpg with 1/4 quart per 1000 mi in trips that included Raleigh, NC to Wilmington and Raleigh to eastern W Va - Harpers Ferry.