Loctite 242 vs 243 – Loctite Threadlocker Comparisons

Loctite 242 and 243 are two of the most popular Loctite products and that’s saying something – they have hundreds of different products to choose from. However, there’s a reason that these two products are their most popular – they’re threadlockers, which are some of the most commonly needed adhesives amongst mechanics.

The difference between Loctite 242 and Loctite 243 is that Loctite 243 is a slightly upgraded version of Loctite 242. You’re unlikely to notice the difference, but 243 actually has a slightly better oil tolerance than Loctite 242.

I say that there’s not a lot of different between the two products, and that’s entirely true – you’re unlikely to notice much of a difference if you haven’t used these products before. But, there is definitely a difference between the two products and if you’re using Loctite 242, then I’m going to convince you of a couple of reasons that you should upgrade to Loctite 243.

Why Loctite 243 is better than 242

There’s no doubt that Loctite 243 is a better option than 242 – Loctite themselves have even said that it’s the upgraded version. But for the majority of people, they won’t upgrade to 243 if they’ve already purchased 242 – why waste the extra cash, it’s basically the same right? Well it’s similar, but it is a bit better and it undoubtedly makes things easier.

However, the difference between the two is really minimal and you’re unlikely to notice much of a difference. I usually pick up Loctite 242 from Amazon if I’m going to purchase it, as it’s the easiest way to get my hands on it – it’s usually only $5 or so.

Loctite Heavy Duty Threadlocker, 0.2 oz, Blue 242, Single
  • Advanced formula prevents loosening of metal fasteners caused by vibrations
  • Protective design protects threads from rusting and corroding
  • Medium-strength allows nuts and bolts to be removed with hand tools
  • Locks and seals threaded fasteners that require disassembly

Lets see why 243 is a better choice for you than going for Loctite 242.

  • It’s stronger – If you haven’t used the two products, then take it from someone that has used both extensively – 243 is a little stronger than Loctite 242. Not by a great deal, but it’s definitely noticeably stronger in my opinion.
  • It’s oil resistant – Of course, the main benefit of using 243 is that it’s more oil resistant than 242. It seems like Loctite listened to what the people want and decided to produce a product that could be easily used for threads.
  • It’s great for lazy people like me – If you’re happy to clean every thread before you’re using it, then you can stick with using 242. But the main benefits for me of using 243 is that it’s oil resistant – this means that it doesn’t matter if there’s still some oil on your threads, you can just apply 243 to it straight away without having to worry about cleaning it up first.

These are the main reasons that I prefer to use 243 instead of 242 – plus, Loctite 243 isn’t particularly expensive either, so you don’t need to worry about the cost aspect of it (I know all the different adhesives can add up!).

Other Loctite Threadlockers I recommend

There are a ton of other Loctite products out there, but I mainly use their threadlockers (like the majority of people, I guess. So, I think I’m in a good position to talk about the best Loctite threadlockers that are currently on the market and to help you understand the differences between them

Loctite 221 & 222 – Low strength

Loctite 221 and Loctite 222 are good options for people looking for a low strength threadlocker – this is suitable for using for small threads up to a maximum size of M12. It has a low viscosity, which basically means that it’s particularly thin, which works for a threadlocker designed for small threads.

Loctite 272 & 278 – Temperature Resistant

If you need something with a medium viscosity which can be used for relatively high strength applications, then Loctite 272 is a better bet for you – its designed to be used for permanent thread locking, so you know it’s going to be high strength.

Loctite 270 & 276 – High Strength

If you want to lock threads up permanently, then you’ll need to opt for a high strength threadlocker. Loctite 270 and Loctite 276 are two high strength threadlockers which fulfil this criteria. Why might you need a high strength threadlocker? Well, it’s an essential to have a high strength threadlocker if you’re dealing with a bolt that is going to be vibrating a lot.

Locktite 290 – Wicking

Wicking threadlockers can be confusing, but generally they’re designed to be extremely low viscosity so that the threadlocker itself can be applied without needing to disassemble anything (it seeps through into the thread). Loctite 290 is available to check out on Amazon here.


There are other Loctite Threadlockers out there, and there’s hundreds of different Loctite products overall, but it’s literally impossible to compare them and show you all of them. Plus, I’d be being a bit sneaky if I recommended products I haven’t used myself – I’ve used all of these products and can attest that they work well!

No matter what you need, it’s worth consider using a Loctite brand threadlocker for best effect – you can also consider using Permatex – Loctite’s biggest competitor, which I wrote a comparison about here. Though, my gut instinct will always to be to reach for the Loctite before anything else!

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