I have a 2002 Suburban with 70,000 on the clock which has slapped from day 1 and runs terrific and quiet as a mouse and no leaks anywhere. I have been using Penzoil 5w30 & Fram or Delco filter since new with first OCI at 100 miles then every 3000 religiously. I have tried valvoline 5w30 dino as well and both seem to slap for the first minute of warm up but both get good oil pressure and I never have to add any except when I drive to Florida and back then I use 1/2 quart in 3000 miles. Does anybody out there know of an oil that quiets the slap? I have been told that this is caused by short piston skirts and has nothing to do with engine longevity. Does anybody know if this is true? It slaps in the Winter AND in Summer heat as well. Thanks for reading this. KB