Loctite 5408 Head Bolt & Water Jacket Sealant – 50 mL
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Regular price
$ 37.95 USD
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LOCTITE® 5408 Head Bolt & Water Jacket Sealant is a charcoal-gray, fluorescent anaerobic threadlocker gel engineered to lubricate fasteners during assembly, lock bolts against premature loosening, and seal threaded gaps. Its lubricating action also helps simplify future removal of fasteners installed through holes into water jackets.
This one-part, medium-viscosity thixotropic gel is ideal for automotive engine service and metal fastener assemblies where sealing, corrosion prevention, and controlled disassembly all matter.
Key Features
- Lubricates fasteners during assembly for more consistent installation
- Locks and seals metal threads to resist vibration loosening and leakage
- Helps eliminate corrosion that can complicate later disassembly
- Fluoresces under UV light for application and quality inspection
- No mixing required; cures anaerobically between close-fitting metal surfaces
- Operating temperature range: -65°F to 300°F (-55°C to 150°C)
Popular Applications
- Head bolts and through-bolts entering water jackets
- Water pump bolts
- Thermostat housings
- Intake manifold bolts
- Temperature sensors and other threaded metal engine components
Product Specifications
| Brand | LOCTITE |
|---|---|
| Product | 5408 Head Bolt & Water Jacket Sealant |
| Henkel IDH | 1158514 |
| Package | 50 mL tube |
| Technology | Dimethacrylate ester acrylic; anaerobic cure |
| Color / Form | Charcoal gray fluorescent gel |
| Components | One part |
| Viscosity | 350,000–950,000 mPa·s (cP) at 25°C |
| Specific Gravity | 1.12 typical (TDS) |
| Breakaway Torque | 18.6 N·m (165 lb-in) typical on M10 steel after 24 hours |
| Compressive Shear Strength | 9 N/mm² (1,330 psi) typical |
| Temperature Range | -65°F to 300°F (-55°C to 150°C) |
| Full Cure | 24 hours typical at 22°C; cure speed varies by substrate, gap, temperature, and activator use |
Application Guidance
- Clean and dry mating threads. Use a compatible LOCTITE activator when cure is slow or inactive surfaces are involved.
- Shake the tube before use. Avoid touching the nozzle to metal.
- For through holes, apply where the nut will engage. For blind holes, apply into the lower third.
- For sealing, apply a continuous 360° bead while leaving the first thread free, then assemble and tighten normally.
Important: Not recommended for pure oxygen or oxygen-rich systems, chlorine, or other strong oxidizers. Not normally recommended for plastics; test compatibility before use. For professional use, consult the current Technical Data Sheet and Safety Data Sheet before handling.
Safety & Shipping
DANGER: Combustible liquid. Causes skin and serious eye irritation. May cause an allergic skin reaction. Suspected of causing cancer; may damage fertility or the unborn child; may cause organ damage through prolonged or repeated exposure. Use appropriate protective gloves, clothing, and eye/face protection. Keep away from heat, sparks, and open flame.
Transport classification from the U.S. SDS (rev. 005.0, issued January 2, 2024): ground—Combustible liquid, n.o.s., NA1993, Packing Group III; air/sea—Environmentally hazardous substance, liquid, n.o.s., UN3082, Class 9, Packing Group III. Carrier and packaging exceptions may apply; ship in accordance with applicable regulations.