There are a lot of older BMWs out there without the original antenna still in place. If you aren't respraying your car and patching the hole there hasn't been a simple solution to keep the hole watertight until now.
Ensure your antenna cutout has not been modified and is the OEM diameter.
An unmodified cutout will measure approximately .85 inches (2.16 cm) in diameter.
Everyone has tried going to the local hardware store and picking up an American standard sized plug to fit in a metric hole. The solution seems like a cheap easy fix until you realize it doesn't fit properly and it doesn't seal the opening to prevent water getting in. You can use silicone but that gets messy and never seals perfectly.
We found these simple antenna delete plugs that are the best solution out there. The antenna delete plugs are simple plug and play installation. They keep the hole the original OEM size without modification and best of all, THEY WATERPROOF THE HOLE WITHOUT MODIFICATION!!
This antenna delete plug is the highest quality plug available with co-molded plastic, the center is made of hard plastic with locking tabs while the outer layer is soft rubber that seals the hole. Although the price may be more than a 63 cents from the local hardware store, the end result is worth it. Treat yourself and get an antenna delete plug. Remember this plug fits ALL E30, E36, E28 and Z3 models.
Internation shipping is extra