2017-2020 BMW Alpina B7 Rear Spoiler: Fitment, Painting, and Inspection Guide

Symptoms of a Damaged Rear Spoiler

As a fixed, non-mechanical part, the Alpina B7 rear spoiler does not 'fail' electronically. Instead, problems are related to physical damage or bonding failure. Symptoms are always visual or audible.

• Loose Fitment or Rattling: If the spoiler feels loose to the touch or you hear rattling from the trunk area, the factory adhesive has likely failed. This is a serious issue, as the spoiler could detach from the vehicle at speed.
• Visible Cracks or Fractures: Impact from road debris or a minor collision can cause cracks. Pay close attention to the mounting areas and thin edges, as these are the most common places for stress fractures to appear.
• Peeling Paint or Clear Coat: Exposure to sun and weather can cause the paint or the protective clear coat to peel, bubble, or fade. While this is a cosmetic issue, it requires the spoiler to be professionally stripped and repainted.

Buying a Used Alpina B7 Rear Spoiler: A Detailed Inspection Guide

A used OEM Alpina spoiler is an excellent way to add factory style to any G11 or G12 7-Series, but a thorough inspection is key. Since even a new spoiler comes in primer and requires painting, the structural condition of a used part is more important than its cosmetic finish.

Physical Inspection Checklist

When inspecting a used spoiler, bring a flashlight and run your hands over all surfaces.

• Check for Part Numbers: Look for the genuine Alpina or BMW part numbers molded into the underside of the part. Common numbers are 4110088 (Alpina) or 51-62-7-992-040 (BMW). This helps verify it's not a cheaper aftermarket replica.
• Inspect for Cracks, Not Scratches: Differentiate between surface scratches that will be sanded away during paint prep, and deep structural cracks. Flex the spoiler gently to see if any hairline cracks open up. Pay special attention to the ends and any sharp edges.
• Look for Warping: Lay the spoiler on a flat surface to check if it's warped. A warped spoiler will not sit flush on the trunk lid and will be impossible to install correctly.
• Examine Previous Repairs: Look for signs of shoddy repair work, like rough patches from body filler (Bondo), uneven surfaces, or drips of old paint. It's often better to buy a part with original, damaged paint than one that has been poorly repaired.
• Ignore Old Adhesive: Don't worry about the condition of the old double-sided tape. It must be completely removed and replaced before installation anyway.

Known Issues, Recalls, and Service Bulletins

There are no recalls or technical service bulletins (TSBs) issued by the NHTSA or BMW for the rear spoiler on the 2017-2020 BMW Alpina B7. Any issues with this part are related to cosmetic condition or physical damage rather than a manufacturing defect.

Cost Comparison: Alpina B7 Rear Spoiler

The main value in buying a used OEM spoiler is the significant cost savings over a new part from the dealer. Aftermarket options exist, but may not have the same quality and fit as a genuine part.

Installation Guide and Difficulty

• Difficulty: 3 out of 5
• Estimated Time: 1.5 hours (includes surface prep)
• DIY Feasible: Yes, for a patient and meticulous person.

Installing the Alpina spoiler is not mechanically complex, but requires precision. The bond is permanent, so you only get one chance to position it correctly. The process involves using high-strength double-sided automotive tape.

Step-by-Step Installation

1. Surface Preparation: This is the most critical step. Thoroughly clean the trunk lid area where the spoiler will mount with isopropyl alcohol to remove all wax, oils, and residue. If your car has a ceramic coating, this area must be polished with a light compound to remove the coating so the adhesive can bond to the paint.
2. Test Fit and Mark Position: Place the spoiler on the trunk and align it perfectly. Use small pieces of painter's tape on the trunk to mark the corners and center of the spoiler. This gives you a visual guide for final placement.
3. Apply New Adhesive: Apply high-quality 3M VHB (Very High Bond) automotive tape to the underside of the spoiler. For the best bond, wipe both the trunk surface and the spoiler's mounting surface with an adhesive promoter first.
4. Final Placement: Peel back a small corner of the adhesive backing from the tape. Carefully align the spoiler with your painter's tape marks and lightly set it down. Once you are certain the position is perfect, slowly pull the rest of the adhesive backing out while pressing the spoiler firmly onto the trunk.
5. Apply Pressure and Let Cure: Work from the center outwards, applying firm, consistent pressure along the entire length of the spoiler for at least 60 seconds to ensure a strong bond. The adhesive needs to cure, so avoid washing the car or driving at high speeds for at least 24-48 hours, especially in cooler temperatures.

Frequently Asked Questions (FAQ)