How to replace a dishwasher door seal

Open the door and pull the door seal out of the channel on the edge of the door.

As you remove the door seal, note which side of the door seal faces the outside of the channel.

Remove the old door seal. 

Thoroughly clean the channel with a mild dishwashing detergent and a cotton swab, because dirt in the channel can keep the new seal from seating and sealing properly.

Let the channel dry completely.

You'll typically find the new door seal creased when you remove it from its package. Warm the gasket with a heat gun or blow dryer on the low heat setting and smooth out any creases or folds.

Fold the seal in half to find its midpoint.

With the correct side of the seal facing out, press the seal's midpoint into the center point of the channel on the top of the dishwasher.

Press the seal into the channel across the rest of the top and evenly down both sides of the door, without stretching the gasket. Press the seal as far into the channel as possible without stretching the seal. An inch or two of seal extend beyond the bottom of the channel on each side to help seal the bottom of the door opening.

Shut the dishwasher door to firmly push the gasket into the channel. Open the door and check the alignment and seating of the gasket. If necessary, remove and reinstall the gasket to ensure a good fit and seal.

Leave the door shut for several hours to permanently set the gasket and help it seal properly