brookspw,

While it is true that the valve guides that M103 motors came from the factory with improved after April of 1989, no valve guide is going to last forever. While the old M103 valve guides could wear as early as 70,000-100,000 miles and the newer ones may last 100,000-120,000 miles, ANY M103 valve guide with 160,000 miles is going to be worn enough to cause serioius oil consumption.