I've been using Pennzoil for quite a few years. I'm very impressed how it stays clean for
many miles. But at the end of the chance period it cleans all the impurities out. I use this in my 06 Dodge Ram, 74 Plymouth Duster, 92 Z34 Lumina, 98 Durango mud toy, my fiance's uses platinum synthetic in her 08 Hemi Charger. Like I said. This is the best oil around. Weather it's for a classic, a play toy, daily driver, or high HP applications.