Understanding Car Door Seals
A car door seal (also called a weatherstrip or weather seal) is a rubber or EPDM strip installed around the perimeter of a car door or its aperture. Its primary function is to create a watertight, airtight barrier between the door and the vehicle body.
Types of Door Seals
On-Body Seals (Door Aperture Seals) Mounted on the vehicle body around the door opening. These are typically the primary weather barrier and feature a bulb-type cross-section that compresses when the door closes.
On-Door Seals Mounted directly on the door itself, usually around the door's inner edge. These provide secondary sealing and help reduce noise.
Window Channel Seals Guide the window glass up and down while preventing water from entering the door cavity. Also known as beltline mouldings or scrapers.
Boot/Tailgate Seals Seal the boot or tailgate opening to prevent water and dust from entering the cargo area.
Materials Used
EPDM (Ethylene Propylene Diene Monomer) The most common and preferred material for modern vehicle seals. EPDM offers excellent resistance to UV, ozone, weathering, and temperature extremes (-40°C to +120°C).
PVC (Polyvinyl Chloride) A cheaper alternative found in some budget aftermarket seals. PVC is less durable and can become brittle in cold weather.
TPE (Thermoplastic Elastomer) Used in some newer vehicles. Combines the flexibility of rubber with the recyclability of thermoplastics.
Signs Your Door Seal Needs Replacing
- **Visible cracks or tears** in the rubber
- **Water leaks** inside the cabin when it rains
- **Increased road noise** at speed
- **Wind whistling** around the doors
- **The seal feels hard** and no longer springs back when compressed
- **Difficulty closing** or the door doesn't latch properly