Scenario: 2001 VW Jetta w/2.0 NA engine, 210,000 miles. Prior oil used was apparently a Castrol 20w-50. Did a fresh oil change with Chevron Delo 400 15w40 and a Champ Labs E-Core filter. Started car and now it blows crazy amounts of blue/grey smoke, but idles just fine. My guess is a piston ring(s) was about to go and the fresh change to a thick oil from the thinned out used oil caused it/them to finally go. Any thoughts? Other opinions? Not my car by the way.