Are there any conventional oils on the market that combat sludge like most of the synthetics? Is Castrol GTX or Pennzoil YB falsely advertising that their respective oils keep my engine clean? I have read many articles online about many different engines by different car makers, some run very clean, some sludge up. There are many websites that state dino oil sludge problems still exist. How do I find out if my engine is a sludge maker? Its a Hyundai Veracruz 3.8L V-6. Which dino oil is better at keeping my engine clean. We plan on keeping this vehicle for a very long time.