Cracked Porsche Boxster Rear Plastic Window – Repair Options

A Critical Issue on Porsche Boxster 986 cars, made before 2003, is dealing with a Cracked Porsche Boxster Rear Plastic Window

Porsche produced the original Boxster with a plastic rear window. The lifespan of the plastic window can be quite low. You need to be careful of both “cold crack” and scratching problems.

In 2003 Porsche upgraded the Boxster to a glass rear screen, however, they changed the pattern at the same time making it impossible to upgrade the old cars with the new convertible top. The new OEM convertible top with a rear glass window, can not be retrofitted onto pre-2003 Boxsters.

Care for Your Rear Plastic Window

If you own a Porsche Boxster 986 with a rear plastic window, you need to be extra careful. Here are some tips for increasing the lifespan of your rear plastic window.

Pedro has had his 1998 Boxster rear plastic window last well over 20 years.

1.0 Do Not Lower the 986 Convertible Top in Cold Weather

Be very careful when opening your convertible top in cold weather. The colder the weather the more prone your plastic rear window is apt to crack. Never operate the convertible top under 55ºF (or 12°C) without a thorough warm-up.

Newer plastic rear windows are very pliable but age sees the rear plastic windows get brittle and inflexible.

Never use your convertible top below 40°F or 5°C!

2.0 Boxster Chop

All owners of a 986 with a rear plastic window need to learn the “Boxster Chop”. You need to get your black belt in this critical defensive maneuver.

When you do lower the top, open the top enough to start the rear window folding then get out of the car and do a ‘chop’ with your arm/hand and make a nice even crease/fold in the window so when you open the top all the way the window doesn’t develop a compound fold/crease.

The “Boxster Chop” is recommended in all weather conditions as a defensive measure.

3.0 Yearly Maintenance of Rear Place Window

If you have a rear plastic window on your Porsche Boxster you need to take extra special care of it. You need to clean and polish it yearly to prevent oxidation (or yellowing and pitting.)

3.1 Clean and Protection of the Rear Plastic Window

The plastic rear window will fog and scratch which is one of the biggest complaints from Boxster owners. Fogging and oxidation happen as the plasticizers evaporate. This is caused by UV Light and the heat from the sun. As a result, the Boxster’s Rear Plastic Window becomes cracked or damaged.

The best way to maintain your plastic rear window is to keep the sun off the plastic rear window as much as possible. Use a good plastic cleaner and UV protectant.

3.2 Polish Your Rear Plastic Window

Rid your read plastic window of minor scuffs, yellowing, and scratches using good plastic polish. Your rear plastic window can be restored using a plastic polishing compound.

Repair Options for your Porsche Boxster Rear Cracked Plastic Window

1.0 Seal the Crack ASAP on Your Plastic Window

Once you notice that your rear plastic window is cracked, you need to act immediately to prevent further damage. Minimize all use of your convertible top until you choose an option to repair the issue.

1.1 Quick Fix for Cracked Rear Window

It is important to seal your cracked window ASAP. You do not want the crack to spread or cause more damage. Lamin-X has a dedicated Convertible Plastic Window Repair solution. Very durable and will stand up to time. It comes with a 5-year warranty.

2.0 Replace the Rear Plastic Window

Many forum Porsche Boxster members have reported excellent service for the rear plastic window from Boat Canvas Repair service shops. All boats make use of canvas covers with plastic windows. Many drivers have received cost-efficient solutions for a quick repair or replacement of the plastic window.

Boat Repair can replace the plastic window at a reasonable price.

3.0 Repair Worn, Torn, or Damaged Convertible Canvas

This is a preferred option if you get your canvas cut because of theft (or break and enter of your car.) These shops can do a quick waterproof seal to your canvas roof.

It is critical that you need to get this on quickly to prevent the holes or tears from spreading. Your fastest and best solution would be to use a canvas patch. We recommend that you use a Gore-Tex canvas patch. You need a 1/2 inch over coverage on the patch and you can cut to size to minimize the size of the patch.

Make sure you get a quote and compare any previous work of the shop.

4.0 Replace the Rear Plastic Window with Glass

For this option, you will need to investigate using a car service repair shop that specializes in convertible tops. I have to warn you though, that the cost for this repair will almost always exceed the cost of the next and preferred option of replacing the entire top..

When getting this quote, also ask for a complete replacement of the top as well. This will give you a good comparison. Please note that the replacement of the rear window will still be the same size and not larger as seen in the post 2003 Boxsters.

5.0 Replacing Your Porsche Boxster Convertible Top

Many 986 owners opt to get a new canvas top, complete with a new glass window. If you’re looking to buy an early Boxster 986, please keep in mind this upgrade and the costs involved.

All Boxster Forum Sites will have multiple dedicated threads on this issue and offer many solutions for resolution.

Please note that Replacing the Convertible Roof is Project 70 in the 101 Projects for Your Porsche Boxster.

6.0 From Amazon

7.0 From the Internet:

Top 5 Recommended Boxster Web Forums (Excellent Resource for repairs and advice)

6SpeedOnline – Rear window ripped, now what?

PedrosBoard – Rear window replacement question for 986

8.0 Be Sure To Join Our FaceBook Group

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Last update on 2025-07-11 / Affiliate links / Images from Amazon Product Advertising API