Permatex Threadlocker 24240 Medium Strength Blue 36 ml — Automotive 1/4"–3/4" Fastener Locking & Corrosion Protection

Permatex 24240 Blue is a medium-strength liquid threadlocker that secures bolts and nuts from vibration while remaining removable with common hand tools.

If you work on engines, drivetrains, or general mechanical assemblies, this 36 ml tube of Permatex 24240 provides a reliable sealing and locking solution for fasteners between 1/4" and 3/4" (6 mm to 20 mm). Formulated to cure anaerobically, it fills gaps in threads, resists loosening from vibration, and helps protect against corrosion across a wide temperature range. The medium strength allows service removal without specialty heating equipment—simply use standard hand tools when disassembling.

How does Permatex 24240 keep bolts from backing out?

The product cures in the absence of air to form a polymer that bonds mating threads and resists rotational forces. It dampens micro-movement between parts, which is a primary cause of loosening under vibration.

• Applies as a liquid then cures to a tough polymer between threads
• Designed for 1/4" to 3/4" fasteners (6–20 mm)
• Reduces risk of workpiece fretting and loosening from vibration
• Prevents small gaps that trap moisture and cause corrosion

What automotive and mechanical parts is this threadlocker suited for?

Permatex 24240 is recommended where medium retention is needed but future service access remains likely. It’s commonly used on engine covers, water pumps, oil pans, and driveline components.

• Valve cover bolts, oil pan bolts, and water pump hardware
• Drive shaft bolts and rocker arm adjustment nuts
• Carburetor studs and similar serviceable fasteners
• Any nut or bolt application within the specified size range

How do I apply and remove this threadlocker correctly?

Clean threads, apply a few drops to the fastener threads, assemble, and allow the adhesive to cure in the absence of air. Removal is done with standard hand tools; if stubborn, warming can speed disassembly.

• Ensure threads are clean and free of oil before applying
• Use a drop or two on bolt threads—no need to coat completely
• Cures anaerobically; allow appropriate cure time per servicing needs
• Disassemble with hand tools; apply controlled heat only if necessary

What performance and environmental limits should I expect?

The threadlocker withstands a broad temperature range and resists corrosion, but its design favors medium-strength applications where future maintenance is anticipated. It performs reliably across common automotive temperature cycles.

• Temperature service range roughly -65°F to 300°F (-54°C to 149°C)
• Protects threads from corrosion caused by moisture exposure
• Medium strength—suitable for serviceable fasteners
• Size coverage: ideal for 1/4" to 3/4" (6–20 mm) fasteners

Who is this product for? Permatex 24240 Blue is aimed at automotive technicians, home mechanics, restoration hobbyists, and maintenance professionals who need a dependable, removable threadlocker for fasteners that require occasional service. If you want to prevent vibration-induced loosening, protect metal threads from corrosion, and still be able to disassemble parts with basic tools, this medium-strength formula offers a practical balance of holding power and serviceability.