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Porsche 993: How to Seal Windshield

Learn how to apply a water-resistant seal between your windshield and car. Simply follow the instructions below.

By Jared Hammond - April 20, 2015
Contributors: Bruce Carter

This article applies to the Porsche 993 (1993-1998).

Making sure that your car windows are properly sealed is vitally important to the health of your car. If water can get underneath the windshield or rear window, it can get trapped there and cause some serious corrosion. There are a couple of ways to fix this, but this article shows you one of the most effective solutions, which is to completely fill the gap between the windshield and car body with a bonding seal.

Materials Needed

  • Wurth bond and seal
  • Porsche windshield outer seal - Part #993-541-925-00
  • Caulk gun
  • Masking tape
  • Packaging tape
  • Steel wool
  • Putty knife
  • Spray bottle
  • Compressed air
  • 3M adhesive remover
  • Nitrile gloves

Step 1 – Remove the outer seal

Find the aligning mark at the bottom center of the windshield. Then, loosen and pull off the rubber seal.

Figure 1. Remove outer seal.

Step 2 – Clean the gap under the windshield

Use steel wool and adhesive remover to clean the gap under the windshield. Clean thoroughly otherwise you'll end up with gaps in the seal. Afterwards, rinse the gap with water and dry it with compressed air.

Figure 2. Clean out the gap under the windshield.

Pro Tip

As a quick and easy fix you could also use a silicone sealant which can be applied without having to remove the old adhesive; however, this doesn't really offer a permanent solution.

Step 3 – Apply seal

Put masking tape all around the window and car body to isolate the gap. You'll also want to mask the channel where the rubber seal sits and wherever the rubber seal touches the car body. Cut the top off the tube of sealant then attach it to your caulk gun. Apply the sealant to the gap, filling in every space.

  • Figure 3. Put masking tape around the gap.
  • Figure 4. Apply the seal using your caulk gun.

Step 4 – Replace outer seal

Wet your finger and drag it along the edge of the gap to smooth out the seal. Make sure none of the seal spilled out from under the windshield. After that, all that's left to do is remove the masking tape and replace the rubber seal along the edges of the windshield. Wait 24 hours for the seal to dry.

Figure 5. Press outer seal in firmly.

Pro Tip

Sometimes, one of the edges of the outer seal will pop out. Put packaging tape along the corners and edges to prevent this. Just don't forget to remove the tape, otherwise it'll leave some sticky residue on your car that's hard to remove.

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