Check the condition of the two thermal pads under the SSD and replace them if they're damaged. If a pad remained intact on the bottom of the old SSD, carefully transfer it to its spot on the board.

If you're changing the type of SSD (single-sided or double-sided), you'll need to change the pads so they're the proper thickness.

To replace a damaged pad:

Make sure your new pad is the correct thickness and size. Pad thickness depends on the type of your replacement SSD—2.25 mm for a single-sided SSD and 0.8 mm for a double-sided SSD.

Use a spudger or your fingers to carefully remove all of the old pad from the motherboard.

Be very careful not to damage any of the small surface-mounted components on the board.

Use highly-concentrated (more than 90%) isopropyl alcohol and a lint-free cloth (or coffee filters) to clean up any thermal pad residue.

Carefully put the new pad onto the board, making sure it goes into the rectangle marked PAD AREA.