How does Shell Helix Ultra work?

Normal mineral oils can allow dirt particles to stick together and form sludge on engine surfaces. This can prevent proper lubrication and could lead to premature engine failure. Shell Helix oils’ active cleansing agents are designed to prevent dirt particles sticking together to form sludge. For example, Shell Helix Ultra removes up to five times as much sludge compared with a normal mineral oil (API SG/CD).