1. Product Overview
Loctite 243 Blue Oil Resistant Threadlocker is a medium-strength, medium-temperature, oil-tolerant anaerobic adhesive. It is specifically formulated for general-purpose automotive and mechanical applications, providing reliable bonding even in challenging conditions.
This threadlocker effectively bonds to all metals, including stainless steel, aluminum, and plated surfaces. It is designed to secure components against heavy shock, vibration, and chemical exposure, making it ideal for rocker studs, adjustment bolts, valve and cam covers, oil pans, disc brake calipers, intakes, alternators, and pulley assemblies. It is suitable for nut and bolt applications ranging from ¼" to ¾" (6 mm to 20 mm).

Image 1: Loctite 243 Blue Oil Resistant Threadlocker 6ml tube.
Benefits of Loctite Threadlockers
Understand the advantages of using Loctite Threadlockers for securing threaded assemblies.
Video 1: Explaining the benefits of using Loctite Threadlockers over traditional fasteners to prevent self-loosening due to vibration.
2. Safety Information
CAUTION:
- May cause allergic skin reaction.
- IRRITANT. Eye and skin contact may cause irritation.
- Use with adequate ventilation.
- Do not swallow.
FIRST AID TREATMENT:
- Contains Methacrylate esters.
- For eye contact, flush with water for 15 minutes.
- For skin contact, wash affected area with soap and water immediately.
- If affected by inhalation, remove to fresh air.
- If symptoms develop or persist, seek medical advice.
- If swallowed, do not induce vomiting. Call a physician or Poison Control Center immediately.
KEEP OUT OF REACH OF CHILDREN.
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
3. Setup and Application
Preparation
- Shake the tube well before use.
- Clean and dry parts with Loctite Primer (Part No. 494147), if available. While Loctite 243 is oil-tolerant, clean surfaces ensure optimal performance.
- Assemble parts and make any necessary adjustments before applying the threadlocker.
Application
- Apply Loctite 243 Threadlocker directly to the threads where the nut and bolt will meet. Ensure sufficient coverage for a secure bond.
- Tighten the assembly to the recommended torque.

Image 2: Applying Loctite 243 Threadlocker to a bolt before assembly.
4. Operating (Curing Process)
Loctite 243 is an anaerobic threadlocker, meaning it cures in the absence of air when confined between close-fitting metal surfaces. It is designed for metal parts and is not recommended for plastic.
- Fixture Time: Parts will fixture (set) within approximately 10 minutes, allowing for initial handling.
- Full Cure: The product reaches its full strength after 24 hours.
- Temperature Resistance: Provides a durable, temperature-resistant bond up to 140°F (60°C).

Image 3: Close-up of Loctite 243 being applied to bolt threads for secure fastening.
5. Maintenance (Disassembly)
Disassembly of Medium-Strength Threadlockers (Loctite 243)
Assemblies secured with Loctite 243 can typically be disassembled using standard hand tools. No special heating is usually required for removal.
Disassembly of High-Strength or Permanent Threadlockers
For assemblies locked with high or permanent strength threadlockers, a different method is required:
- Apply localized heat to the nut or bolt to approximately 250°C (482°F).
- Disassemble the parts while they are hot.
Video Guide: How to Disassemble Threadlocked Assemblies
Watch this video for a visual guide on disassembling threadlocked components.
Video 2: Demonstrating the process of disassembling components secured with Loctite threadlockers, including methods for different strength levels.
6. Troubleshooting
Product Not Curing
- Ensure the product is applied between metal surfaces with minimal air exposure. Anaerobic adhesives require the absence of oxygen to cure.
- Verify that surfaces are clean and dry. While Loctite 243 is oil-tolerant, excessive contamination can hinder curing.
- Check ambient temperature. Curing times may be longer in colder conditions.
Difficulty in Disassembly
- For Loctite 243 (medium strength), standard hand tools should suffice. If resistance is high, ensure proper leverage.
- If a stronger threadlocker was mistakenly used or if the bond is exceptionally strong, refer to the heat application method described in the Maintenance (Disassembly) section.
7. Specifications
| Attribute | Value |
|---|---|
| Brand | Loctite |
| Model Number | 1330799 |
| Specific Uses | Automotive, Mechanical |
| Material Compatibility | Aluminum, Stainless Steel |
| Item Form | Liquid |
| Color | Blue |
| Item Volume | 6 Milliliters |
| Viscosity Level | Medium |
| Full Cure Time | 24 Hours |
| Water Resistance Level | Water Resistant |
| UPC | 079340439078 |
8. Warranty Information
Specific warranty details for the Loctite 243 Blue Oil Resistant Threadlocker are not provided in the product information. Please refer to the manufacturer's official website or contact Loctite customer service for detailed warranty terms and conditions.
9. Support Information
For technical assistance, product inquiries, or further support regarding your Loctite 243 Blue Oil Resistant Threadlocker, please visit the official Loctite website or contact their customer support channels. Contact information may vary by region.





