Liqui Moly Engine Oil Additive 3721 - 1‑Unit Concentrated Lubrication & Deposit Control

Liqui Moly 3721 Engine Oil Additive is a concentrated formula designed to improve lubrication, reduce wear and deposits, and maintain oil system cleanliness when added to engine oil.

Built by Liqui Moly, a specialist in automotive chemical products, this engine oil additive is formulated for use in a wide range of gasoline and diesel engines. It blends with existing engine oil to enhance film strength, stabilize performance under high thermal and mechanical stress, and remain compatible with standard oil filters and sealing materials. The product ships without a core charge and is offered as a single-quantity unit for straightforward application during oil changes or maintenance intervals.

How does this additive improve engine lubrication?

Liqui Moly 3721 supplements the base oil’s lubricating properties by reinforcing the oil film between moving metal parts. That reduces metal-to-metal contact and helps prevent scuffing and premature wear, especially under heavy loads or elevated temperature conditions.

• Enhances oil film strength to protect bearings and cam surfaces
• Formulated to remain stable during sustained high thermal and dynamic loads
• Works as a complement to regular engine oils rather than replacing them

Will it keep the oil system clean and prevent deposits?

The additive is designed to minimize deposit formation and maintain fluid cleanliness so filters and pathways stay clear. It’s developed to be chemically compatible with common filtration systems, lowering the risk of clogging or reduced flow.

• Reduces buildup on pistons, rings, and valves
• Formulated for compatibility with typical engine oil filters
• Helps preserve oil flow characteristics between service intervals

Is this safe to use with my existing engine and seals?

Liqui Moly 3721 is crafted to be fully compatible with commonly used sealing materials and engine components when mixed with conventional engine oils. It does not require changing seals or other parts and is safe for standard maintenance routines when used as directed.

• No special hardware changes or seal modifications needed
• Tested for compatibility with widely used filter and seal materials
• Applies readily during routine oil top-ups or full oil changes

How and when should I apply this additive?

Apply the additive directly into the engine oil during an oil change or before a long operating cycle. Follow the manufacturer’s recommended dose relative to the engine’s oil capacity to achieve optimal effect without over-concentrating the oil.

• Add during oil replacement or prior to extended driving conditions
• Mixes into existing engine oil—no flushing required
• Use the specified quantity per engine oil volume for best results

Who is this for? Liqui Moly 3721 Engine Oil Additive is aimed at vehicle owners, fleet operators, and professional mechanics seeking to extend component life, reduce wear, and maintain oil system cleanliness without major interventions. It suits routine maintenance schedules for passenger cars, light commercial vehicles, and machinery where improving lubricant performance and deposit control are priorities. If you want a concentrated, filter-compatible additive to complement your engine oil during service, this product provides a straightforward, no-core-charge option from a recognized specialist in lubricant additives.