Loctite threadlocker 243 Blue Medium-Strength 250 mL Bottle — oil-tolerant, removable with hand tools

Loctite 243 is a blue, medium-strength threadlocker in a 250 ml bottle designed to lock and seal threaded fasteners while tolerating light oil contamination.

Engineered for general-purpose industrial and maintenance use, this threadlocker balances secure holding with the ability to remove fasteners with normal hand tools. Its formulation tolerates typical surface oils and does not require perfect cleaning before application, making it suitable where quick maintenance or on-the-spot repairs are common. This product cures anaerobically when confined between metal parts and helps prevent loosening caused by vibration and thermal cycling.

How does Loctite 243 perform on lightly oily or as-received fasteners?

The 243 formula includes improved oil tolerance so it can cure effectively on fasteners that haven't been fully degreased. While full cleaning yields the strongest bond, this product was developed to work reliably on standard factory-finished or slightly contaminated parts.

• Oil-tolerant curing on as-received fasteners without cleaning
• Designed for metal-to-metal threaded assemblies
• Medium strength allows later removal with hand tools
• Reduces need for immediate degreasing in maintenance settings

What strength and temperature limits should I expect from this threadlocker?

Loctite 243 is categorized as medium-strength, offering secure locking while still permitting disassembly using standard tools. It withstands a broad range of operating temperatures but manufacturers specify the maximum temperature for temporary resistance.

• Medium-strength formula for balanced locking and removability
• Rated up to 360 degrees Fahrenheit (maximum temperature tolerance)
• Suitable for assemblies exposed to vibration and moderate heat
• Not intended for permanent, high-torque, or extreme-temperature joints

How should I apply and store the 250 ml Loctite 243 bottle?

Apply a drop or two to the male threads where it will be confined between the screw and mating part; avoid excess that could squeeze out. Store the bottle capped in a cool, dry place to preserve shelf life and prevent premature curing from exposure to air or metal contamination.

• Apply sparingly to male threads for best cure and economy
• Assembled joint cures anaerobically (in absence of air) between metal parts
• Keep bottle tightly closed and store at recommended temperatures
• 250 ml size suits workshops, maintenance departments, and repeated use

Who is this for? Loctite 243 in a 250 ml bottle is aimed at mechanics, maintenance technicians, fabricators, and hobbyists who need a dependable medium-strength threadlocker that handles routine surface oils. It’s well suited for general industrial applications, automotive repairs, and equipment maintenance where the combination of oil tolerance, reliable locking, and removability matters. If you need a permanent, high-temperature or structural adhesive, consider alternative Loctite grades designed for those extreme requirements.