2004-2008 Audi S4 Rear Spoiler: Decoding Sedan, Avant & DTM Differences

Key Variants: Sedan, Avant, and Cabriolet

The most critical factor when purchasing a rear spoiler for a 2004-2008 Audi S4 is ensuring it matches your vehicle's body style. The spoilers are not interchangeable between the Sedan, Avant (wagon), and Cabriolet (convertible) models due to significant differences in the trunk and tailgate shapes.

• Sedan (2004-2008): Fits the B6 and B7 generation sedans. These spoilers are designed for the specific curvature of the sedan's trunk lid. OEM part numbers for sedans typically begin with 8E5.
• Avant (Wagon) (2004-2008): These are often called roof spoilers, as they mount to the top of the rear tailgate. They will not fit a Sedan or Cabriolet. OEM part numbers for the Avant typically begin with 8E9.
• Cabriolet (Convertible) (2004-2009): The convertible has a unique trunk lid and often a more subtle, integrated lip spoiler. Spoilers from Sedans or Avants will not fit.

The Special DTM Carbon Fiber Spoiler

For the B7 generation (2005.5-2008), Audi released a limited-production S4 '25quattro' and a European 'DTM Edition'. These models featured a distinctive factory-installed spoiler made from genuine carbon fiber. This is a highly sought-after part by enthusiasts for its aggressive look and light weight.

• Authenticity: Genuine DTM spoilers are rare and valuable. When buying used, check for the quality of the carbon weave and the official Audi part number. Be cautious of cheaper aftermarket 'DTM style' replicas, which may be fiberglass wrapped in a carbon fiber layer or have a lower quality finish.
• Fitment: The OEM carbon fiber spoiler was designed for the Sedan body style only.

Symptoms of a Failing or Damaged Spoiler

Since the rear spoiler is a non-mechanical part, 'failure' typically refers to cosmetic issues or problems with its mounting.

1. Clear Coat Peeling and Fading

The most common issue is the failure of the protective clear coat. Long-term exposure to sun and UV rays breaks down the top layer of the finish, leading to a cloudy, hazy, or peeling appearance. This starts on the top surfaces and will worsen over time, exposing the paint or carbon fiber underneath to damage.

2. Cracks or Gouges

Impacts from road debris, backing into an object, or closing the trunk on an obstruction can cause physical damage. On fiberglass or ABS plastic spoilers, this can appear as cracks, chips, or deep gouges. On carbon fiber spoilers, an impact can cause the resin to crack or the underlying weave to fracture.

3. Loose Fitment or Rattling

The factory spoiler is mounted with both bolts and strong adhesive tape. Over time, or due to improper installation, this mounting can fail. Symptoms include the spoiler feeling loose to the touch, vibrating at speed, or a noticeable rattling sound coming from the trunk area.

4. Water Leaks into the Trunk

If the seals or gaskets around the spoiler's mounting bolts degrade or were not installed correctly, water can seep through the bolt holes and into the trunk. This can lead to a damp trunk carpet, mildew smells, or moisture around the trunk light and emergency toolkit area.

Buying a Used 2004-2008 S4 Rear Spoiler

A used OEM spoiler is often a great value, but careful inspection is key to getting a good part.

Step 1: Verify Compatibility

First, confirm the spoiler came from a vehicle with the same body style as yours (Sedan or Avant). Ask the seller for the part number if possible and match it against the known OEM numbers.

Step 2: Physical Inspection Checklist

• Check the Finish: Look for signs of clear coat peeling. Minor fading can sometimes be corrected with polishing, but flaking or peeling means the spoiler needs to be completely sanded and repainted.
• Inspect for Cracks: Carefully check the entire surface, paying close attention to the corners and the area around the mounting points. Stress cracks can form near the bolts.
• Examine Mounting Points: Ensure all mounting studs are present, straight, and the threads are in good condition. On spoilers that use adhesive, check that the mounting surface is flat and free of old, hardened glue that would prevent a new bond.
• Look for Signs of Repair: Uneven surfaces, wavy textures, or mismatched paint can indicate a previous, low-quality repair.
• For Carbon Fiber: Check for yellowing or clouding in the resin, which indicates sun damage. Inspect for delamination, where the top layer of resin separates from the carbon weave.

Step 3: Plan for Painting

Most used spoilers will not perfectly match your car's paint color due to fading or coming from a different colored vehicle. Even if the color is the same, there may be scratches or chips from use. Expect to have a professional body shop prep and repaint the spoiler to match your vehicle. Many new OEM spoilers, identified by a 'GRU' suffix in the part number (e.g., 8E5827933GRU), come in a primer finish and require painting from the start.

Installation Overview

Installing a rear spoiler on a B6/B7 S4 is a manageable DIY project for those with basic tools.

• Difficulty: 2 out of 5
• Tools Required: Socket set, trim removal tools, heat gun (recommended), adhesive remover, cleaning alcohol.
• Process (Sedan): The process involves removing the inner trunk lid liner to access three mounting bolts. The factory also uses strong adhesive, which must be carefully softened with a heat gun and cut through with a trim tool or fishing line. After removing the old spoiler, the surface must be thoroughly cleaned of all old adhesive before installing the new one.

Cost Comparison for an S4 Sedan Spoiler

Recalls and Technical Service Bulletins (TSBs)

As of this writing, there are no recalls or TSBs issued by the NHTSA or Audi specifically for the rear spoiler on the 2004-2008 Audi S4. Recalls for this vehicle primarily concern the Takata airbag inflators.

OEM Part Numbers

This list includes known part numbers. Note the prefix difference between Sedan (8E5) and Avant (8E9). The 'GRU' suffix indicates a primed part requiring paint.

• 8E5-827-933-D / 8E5827933D (Sedan)
• 8E5827933A (Sedan)
• 8E5827933GRU (Sedan, Primed)
• 8E9-827-933-A-GRU / 8E9827933AGRU (Avant, Primed)
• 8E9827933C / 8E9827933CGRU (Avant, Primed)

Frequently Asked Questions (FAQ)