Thermal paste still fine after re fitting the cooler?

Bites za dust · July 3, 2020

Hey guys so I just applied some thermal paste to my cpu couple months back actually a guy applied it from whom I bought the cpu and the cooler from at the time I didn't notice that the cooler was dirty and now i want to know if i remove the cooler and clean it (the heatsink and fan part) and fit it in the system again .. will the old thermal paste still work or do i really have to order some more thermal paste

Levent · July 3, 2020

You can make it work but I highly suggest you to get some, its always good to have some even if you clean your computer once a year.

Master Disaster · July 3, 2020

5 minutes ago, Bites za dust said:

Hey guys so I just applied some thermal paste to my cpu couple months back actually a guy applied it from whom I bought the cpu and the cooler from at the time I didn't notice that the cooler was dirty and now i want to know if i remove the cooler and clean it (the heatsink and fan part) and fit it in the system again .. will the old thermal paste still work or do i really have to order some more thermal paste

The issue with heat paste is not that you exposed it to air or broke the bond of the layers, the issue comes from the refitting process. Because the paste is very viscous and already applied to both surfaces its possible to get air bubbles trapped in the paste when you put the HSF back on to the CPU and air is a very good insulator of heat.

In like 90% of the cases reusing old heat paste will be fine however there is always that small chance you'll get unlucky and trap some air. If you do try it without changing the paste and you notice a change in temp then you should remove the paste, reapply it and remount.

One thing to mention, if the heat paste is very old and has started to dry out then it should always be removed and reapplied but you're talking years, not weeks or months.

porina · July 3, 2020

Not best practice, but something you can get away with. The trick is to keep the paste clean, as dust and other stuff can collect in it. Obviously best avoided.

Alternatively, just clean it as best you can without removing if you really don't want to buy new paste. Good stuff will last years anyway so it is practically a one time cost unless you build or refurbish a lot of PCs.