Liqui Moly Catalytic-System Cleaner 300ml — Colourless fuel system cleaner for intake, combustion & catalytic maintenance

LIQUI MOLY 8931 Catalytic-System Cleaner is a 300ml additive formulated to clean deposits from the intake tract, combustion chamber and catalytic system without tinting fuel.

This concentrated, colourless formula is designed for periodic maintenance to reduce build-up that affects fuel flow and exhaust aftertreatment performance. Supplied in a 300ml can, it contains a blend of detergents and specialty additives aimed at dissolving soot, varnish and carbon residues typical of modern petrol and diesel engines. It is packaged compactly and lightweight for easy storage and garage use.

How does this cleaner work inside the intake and combustion areas?

The product uses a targeted combination of cleaning agents that break up and dissolve deposits deposited by fuel and oil combustion. As the vehicle runs, the active ingredients circulate with the fuel or treatment air, loosening varnish and carbon so they can be expelled through normal combustion and exhaust. It is uncoloured to avoid altering fuel appearance.

• Active detergents formulated for intake runners and valve areas
• Solvents that help remove soot and varnish from combustion chambers
• Compatibility with catalytic converters when used as directed
• Colorless formulation avoids fuel discoloration

When should I use the Catalytic-System Cleaner for best results?

Use this cleaner as part of scheduled maintenance or when you notice reduced responsiveness, rough idling, or increased exhaust deposits. It’s suitable before emissions testing or after prolonged low-speed driving that tends to increase deposit formation. Follow the manufacturer’s directions for dosing to ensure effective treatment.

• Recommended during routine service intervals or before inspections
• Helpful after long idling or frequent short trips
• Prepares the catalytic system and sensors for accurate emissions readings
• Simple do-it-yourself application with clear dosing guidance

Is this safe for modern engines and emission systems?

Formulated for compatibility with catalytic converters and exhaust aftertreatment systems, the cleaner avoids ingredients that could damage sensors or catalyst substrates. When used as directed, it helps keep the catalytic system free of insulating deposits that reduce efficiency. Always follow vehicle manufacturer recommendations and the product instructions on the label.

• Designed to be safe for catalytic converters when applied correctly
• Non-tinted to prevent contamination concerns
• Suitable for petrol and many diesel applications — check vehicle guidance
• Low-dose, concentrated 300ml container for multiple or single treatments depending on vehicle size

How do I apply the 300ml treatment step-by-step?

Application is straightforward: add the specified amount to the fuel tank or follow the in-take cleaning instructions provided by Liqui Moly for direct induction use. Run the engine for the recommended duration to allow active ingredients to circulate and break down deposits. Dispose of the empty can responsibly after use.

• Use the dosing instructions printed on the 300ml can for correct amounts
• Add to the fuel tank or use induction method per label guidance
• Operate the vehicle as recommended to distribute the cleaner fully
• Package dimensions: 17.6cm L x 5.0cm W x 5.0cm H; weight about 0.299 kg

Who is this product for? LIQUI MOLY 8931 is aimed at vehicle owners, DIY mechanics and professional workshops looking to maintain intake and catalytic-system performance without changing fuel appearance. It suits drivers wanting a preventive treatment to reduce deposit-related drivability issues, fleets requiring emissions upkeep, and technicians who need a compact, concentrated cleaner that’s easy to store and apply. Always consult your vehicle manual and the product label for compatibility and dosing instructions.

Ingredients

Catalytic-System Cleaner