Permatex 56521 High Performance Thread Sealant, 50 ml, White

used it to seal the differential plugs on my Ram 1500. It worked perfectly! The application was smooth and easy, and it provided a strong, leak-proof seal that gives me peace of mind. I really appreciate that it’s designed for high-temperature environments, which is essential for automotive applications. After driving for a while, I’ve had zero leaks and everything is holding up great. The tube size is convenient and has plenty of product for multiple uses. If you need a reliable, high-performance thread sealant for your vehicle, this is an excellent choice. Highly recommend for anyone doing differential or drivetrain work!

I found this Permatex thread sealant really helpful when working on engine parts. it’s small but goes a long way and keeps leaks tight under heat. I’ve used it during repairs in my garage, and it’s stayed durable. works well and I’m glad I chose it.

I was installing a three-way valve and I didn’t have the means to pressure test my threaded connections until everything was threaded and sweated in place. Once the rest of the fittings were sweated together, I couldn’t tighten the threaded connections. The first time around, I used teflon tape and it didn’t work well. Next, I tried this permatex sealant because it would make a permanent anaerobic seal, and it can withstand sweating connections nearby. It worked great! The connection has been holding for months now with no water leaks. I recommend wearing nitrile or latex gloves when handling, it’ll let you work more quickly and cleanup easier.

Product seems to work fine. However, I purchased the small (6ml) tube and I could barely squeeze out two drops to seal a temp sender. This tube DEFINITELY did not contain 6ml. Otherwise I would have given it 5 stars as I like better than tape.

I use this for every metal to metal pipe fittings. Teflon tape is good but this thread sealant is much better and easier to use because it allows adjustment of the fittings to line up fittings which doesn't work when using Teflon tape. I make sure final adjustments are made within 1 hour as this sealant does cure in the absence of air in the close fitting metal to metal part of the joint and fully cures in 24 hours. If using on stainless steel or anodized aluminum or other inactive metals it's recommended that you use Permatex Surface Prep Activator to ensure proper cure. I was curious about using it on PVC, Permatex says it's NOT recommended for plastic fittings such as PVC. So I plumbed my shop with PVC and used teflon between the male PVC fittings and female metal fittings on all of my air drops and then use this Permatex 56521 sealant for everything else and it has worked without fail for more than 20 years. It's important if you use pvc to metal pipe be sure that the pvc fitting is the male and threaded into a female metal fitting. If you do it the other way around and use female pvc and thread male metal pipe into the pvc fitting it will expand the pvc over time and it will result in a leak. Just what I learned and hope it helps you out

good product for use on automotive threads. was using this after changing transfer case fluid and differential fluid. always works well and when used properly no leaks!

Works great, excellent product for the money.

Use case was to apply sealant to my new rear brake pressure switch for my Harley-Davidson Sportster XL1200C. Applied evenly and this little tube has WAY more (like at least 10X more) than I needed but will be a good addition to the shop. Excellent quality, but note you will have to massage the tube well to get all the fluid to mix easily for a consistent application. Recommended! Don’t settle for less than Permatex. Great value for money and flows evenly.