LOCTITE 518 Automotive Anaerobic Gasket Maker & Flange

LOCTITE 518 is a medium-strength anaerobic gasket maker engineered to form reliable, sensor-safe seals between close-fitting metal flanges and housings.

Built to cure where air is excluded, LOCTITE 518 fills gaps up to 0.25 mm and tolerates light contamination from oils and common maintenance fluids. Its thixotropic formula reduces run-off during application and provides immediate low-pressure resistance after assembly, making it a practical choice for repairs and OEM-level maintenance across engines, transmissions, and gearboxes.

How does LOCTITE 518 create a durable flange seal?

LOCTITE 518 cures anaerobically — that is, it hardens when trapped between metal surfaces where oxygen is excluded. The cured seal resists minor pressures and remains flexible enough to handle thermal and mechanical stress in typical automotive assemblies.

• Cures between close-fitting metal faces and flanges for a formed-in-place gasket
• Gap fill up to 0.25 mm (0.01 in)
• Medium-strength bond allowing later disassembly with tools
• Thixotropic consistency minimizes migration during application

Will it work on aluminum and other passive metals?

Yes — LOCTITE 518 is formulated to work on both active metals like mild steel and on passive substrates such as aluminum with low copper content. It maintains performance even when surfaces have light contamination from cutting or protective oils.

• Compatible with aluminum, iron, and steel flanged mating surfaces
• Tolerant of minor surface contaminants including lubricants and cleaners
• Suitable for mixed-metal assemblies common in automotive components

Is it safe around sensors and electrical parts?

LOCTITE 518 is labeled sensor-safe and low-odor, intended for use on assemblies where sensitive components are nearby. While it’s not an electrical insulator, it cures without producing corrosive byproducts and is non-corrosive to typical automotive metals when used as directed.

• Sensor-safe formulation reduces risk to nearby electronic systems
• Low odor and non-corrosive behavior during cure
• Recommended for engine, gearbox, and transmission housings where sensors are present

How do I apply LOCTITE 518 for best results?

Prepare mating surfaces by removing excess grease and loose debris; light oils and residues are tolerated but heavy contamination reduces performance. Apply a continuous bead to one flange, assemble within cure time, and allow anaerobic polymerization to complete under clamped conditions for full seal strength.

• Clean surfaces of dirt and heavy grease before application
• Apply bead to one side, assemble parts, then tighten to specified torque
• Allow cure time per manufacturer before exposing to pressure or fluids

Who is this for: LOCTITE 518 is aimed at professional mechanics, motorsport crews, and DIY enthusiasts who need a dependable flange sealant suitable for on-the-spot repairs or planned maintenance. It’s particularly useful when conventional gaskets are unavailable or when a formed-in-place gasket offers better sealing for complex housings. Choose this product for transmission covers, engine casings, gearboxes, and similar close-fitting metal assemblies where a medium-strength, sensor-safe sealant is required.