In many older cars the rubber door seals don't seal the way they should. Often the seals have pulled away from the door frame and leave gaps between the frame and the seal, almost always in the corners. This lets in cold or hot air, sometimes water and almost always excess noise. So many older cars have a noisier, drafty ride because the seals are not tight.
Many people think that the reason for the seals not staying in the frame is that they have come unglued. They will often try to glue them back in place but the seals will not stay there. That is because they are not glued in to begin with. The door seals are held in place by simple pressure. When the rubber seals get older the rubber shrinks, the older the seal the greater the shrinking. As it shrinks it pulls away from the door frame almost always at one of the corners. No matter how much glue you use you will not get the seal to stay in place because the seal is now to small to fit the opening. But there is a simple and very cheap fix for the problem that is permanent. You have to make the door seal bigger. Its a lot easier to do than you might think.
Step 1: Find the seam where the seal is joined
The first thing to do to fix the problem is find the seam were the seal is joined. This will almost always be located under the plastic sill that protects the bottom of the door frame. Pry the sill up and off to get access. If yours is screwed down then remove the screws. Most have plastic connectors that go into holes in the floor and they are just pressed in place. They should pull up easily.
Once you have that out of the way you should see the place where the deal is joined. It will probable look like it has been glued or fused together. This is the easiest place to cut the seal. Most of these seals have a metal component running through them to make them rigid and cutting it can be hard. The seam has no metal so you can slice it through with a razor knife or a pair of heavy duty scissors.
After you have cut it you can push the seal back into the door frame corners where it is supposed to be. Sometimes it easiest to pull a section off and then start at the top pushing it back tight working your way back to where you cut it. Now you will be able to see how much your seal has shrunk.