Here is the thing most people do not realise: Loctite and Permatex are both owned by the same parent company, Henkel. Their products are extremely similar in formulation, and in many cases the performance difference is negligible. So when you see heated debates online about which is “better,” the honest answer is that for most applications, either will do the job.
That said, there are genuine differences in product range, availability, and specific formulations. In this guide, I compare them head-to-head across threadlockers, thread sealants, and gasket makers.
Quick Comparison
| Category | Loctite | Permatex | Verdict |
|---|---|---|---|
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|
Loctite 272 | Permatex 27140 | Tie — nearly identical |
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|
Loctite 243 | Permatex 24240 | Loctite 243 (oil tolerant) |
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|
Loctite 222 | Permatex 24024 | Tie |
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|
Loctite 290 | No equivalent | Loctite wins |
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|
Loctite 518 | Permatex 5183 | Permatex (wider gap fill) |
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|
Very wide | Moderate | Loctite |
| Availability | Good | Excellent | Permatex |
Threadlockers Compared
Threadlockers prevent bolts and screws from loosening due to vibration. Both brands use a colour-coded system: red for high strength, blue for medium, and purple for low.
Red Threadlockers (High Strength — Permanent)
Red threadlockers are for permanent applications. You need heat (typically 250C / 500F) to break the bond. Used on cylinder head bolts, bearing cap bolts, and structural assemblies.
| Spec | Loctite 272 | Permatex 27140 |
|---|---|---|
| Strength | High | High |
| Max Temperature | 230C (450F) | 204C (400F) |
| Breakaway Torque | 28 Nm | 25 Nm |
| Removal | Heat required | Heat required |
Verdict: Loctite 272 has a slight edge in temp resistance and torque, but for most applications the difference is academic.
Blue Threadlockers (Medium Strength — Removable)
Blue threadlockers are the workhorse products most people need. They prevent vibration loosening but can be removed with standard hand tools. Perfect for brake calipers, rocker studs, valve cover bolts.
| Spec | Loctite 242 | Loctite 243 | Permatex 24240 |
|---|---|---|---|
| Strength | Low-Medium | Medium | Medium |
| Oil Tolerant | No | Yes | No |
| Primer Required | Yes (inactive metals) | No | No |
| Breakaway Torque | 5 Nm | 26 Nm | 17 Nm |
Verdict: Loctite 243 wins this category. Its oil tolerance means you can apply it to threads that are not perfectly clean — a real-world advantage on engines and machinery.
Purple Threadlockers (Low Strength — Adjustable)
For small screws and fasteners that need regular adjustment. Both Loctite 222 and Permatex 24024 perform virtually identically. Choose whichever is available and cheaper.
Thread Sealants Compared
Thread sealants prevent leaks in pipe threads and hydraulic fittings — a different job from threadlockers. Both brands offer PTFE-based and anaerobic sealants. For standard pipe sealing, either brand works fine. Loctite has a wider range of specialist sealants for high-temperature and chemical-resistant applications.
Gasket Makers: Loctite 518 vs Permatex 5183
Both are anaerobic gasket makers for metal-to-metal flange sealing. The key difference:
- Loctite 518: Fills gaps up to 0.25mm (0.01 inches)
- Permatex 5183: Fills gaps up to 0.38mm (0.015 inches)
If your flanges have wider tolerances, Permatex 5183 gives more margin. Note: Loctite 518 can be hard to find — Loctite 515 is a good substitute but sets faster, so be aware when working with active metals like brass.
Which Brand Should You Choose?
- Blue threadlockers: Loctite 243. The oil tolerance is a genuine advantage.
- Red threadlockers: Either brand. Minimal performance difference.
- Wicking applications: Loctite 290. Permatex has no direct competitor.
- Gasket making: Permatex 5183. Wider gap fill and easier to find.
- Availability: Permatex is easier to find in auto parts stores. Loctite is more common in industrial supply.
[PERSONAL EXPERIENCE] My Go-To Threadlockers
[Adam: Share which specific products you keep in your workshop, what you use them on, and any experience where the choice of threadlocker actually mattered.]
Frequently Asked Questions
Are Loctite and Permatex made by the same company?
Yes. Both are owned by Henkel. Despite shared ownership, the product lines are maintained separately.
Can I mix Loctite and Permatex threadlockers?
Do not apply one over the other. Fully clean existing threadlocker from threads before applying a different product.
Do I need red or blue threadlocker?
Blue for 90% of applications. Red only when the fastener should never come loose without heat. When in doubt, use blue.
How long do threadlockers last once applied?
Properly applied threadlockers last the life of the assembly — years in practice, unless exposed to temperatures above their rating or chemical solvents.
