24 FebKeeping Water Out – Door Seal Drain Holes

While in a modern car recently, I noticed three holes made in the door sealing rubbers for drainage. I couldn’t find any such holes on my Spitfire, and this explains why water still manages to sneak in every so often onto the inner sills and subsequently, the footwells.

After making similar holes in the Spitfire, the problem is virtually gone. Instead of pooling in the groove between the two parts of the door seal, and flooding over it into the car, high volumes of water fall down the holes and onto the outer sill, leaving the car completely.

You don’t want to make the holes too large, otherwise the seal would become ineffective for its main purpose. It probably helps to space the hole at the top of the seal, and the hole at the bottom of the seal, about 1 inch away from eachother to avoid any chance of water splashing up through the holes from outside the car.

Here’s a diagram. Imagine the black line is the flexible part of the rubber seal that goes around the door aperture. The red dots are where you would make the holes.

Here are a few photos showing it done quickly in my car. I used a bradawl and scissors to make slight holes, a better job would be to make the holes more circular. The resulting hole should be quite hard to see however, unless you’re pulling the rubber part of the seal outwards to see it.

That’s one of the holes at the top. Notice how the groove between the 2 parts of the seal has a brown tint – that’s because water runs along this edge, leaving muck after it leaves. That alone should show you why these holes are important.

This second photograph shows one of the lower holes. When making these, be careful that the hole doesn’t cause water to exit too close to the seam that joins the outer and inner sill – you want the water to escape, not be pressed up between the rubber and the sill.

Something like this would probably be fine, maybe make the lower hole a little closer to the bottom of the rubber tube section. You’d have to use your judgement as it will depend on where the rubber sits relative to your car’s outer sill.