How Long Does Thermal Paste Last Once Opened?

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Thermal paste is a common PC accessory that improves heat transfer by filling tiny air gaps between a computer's circuit boards and accompanying heat sinks. If you've invested in some used PC parts, you may need a tube of thermal paste to properly install your new peripherals. Replacing your laptop's thermal paste may be in the cards if you notice your computer is running hotter than usual, leading to unplanned shutdowns when you least expect them. But because thermal paste has such specific use cases, you'll probably be left with a good amount in the tube after you've completed your DIY job.

This begs the question: How long does thermal paste last once opened? Generally speaking, you should be able to use an opened tube of thermal compound for up to 2-5 years. Some paste brands claim you'll get up to 8 years of use, but we'd stick to the lower end as a safe bet. 

You'll also want to keep your eyes peeled for any amount of liquid or dry flakes that come out of the tube alongside the typically grey paste, as the former usually indicates the thermal compound has started to separate. A failing compound may also have a peculiar smell. Fortunately, thermal paste isn't too expensive: a new tube typically costs between $10-15, and as long as you store it correctly, it should be able to maintain its full shelf life.

In most cases, the factory-applied thermal paste on PC peripherals should last for many years. And if you're the kind of user who frequently updates your hardware anyway, you probably won't need to worry about replacing thermal paste. Should you ever find yourself needing to replace a CPU or GPU (and you should never buy these PC parts used), though, your first order of business is removing the old paste from whatever boards and heat sinks you're working with.

You can use isopropyl alcohol and a lint-free cloth to remove the old compound. When applying your new paste, a little goes a long way; just a pea-sized amount is usually enough, which you should apply to the center of your CPU/GPU. Then place the heat sink onto the processor, applying gentle pressure to spread the paste evenly. If you're feeling up to it, you can also use a spreading tool or credit card to spread the paste beforehand.

When your PC job is wrapped up, make sure to screw your thermal paste's cap back on tightly, and then stick the whole tube in a Ziploc bag. You should also store the leftover compound in a cool, dry place away from direct sunlight, extreme temperatures, and humidity.

Even if you've been sitting on a tube of thermal paste that's never been opened, it still has a recommended shelf life — with a ballpark range of about four years. If you're not sure how long you've had an unopened tube for, the expiration date should be printed somewhere on the product. And much like an opened tube of paste, you'll want to store your unopened tube in a cool, dry place away from extreme temperatures and humidity.

Whether you're building a new PC, swapping parts, or addressing an overheating issue, a tube of thermal paste — old or new — is going to be a vital part of your upgrade, maintenance, or repair. When in doubt about the age of an opened tube (and if you can't find the expiration date for some reason), we always recommend purchasing a new batch. Arctic MX-4 Premium Performance Thermal Paste is one of the top-rated products on Amazon, based on over 97,000 reviews, and at full price, you'll only pay $9 plus tax for it.