2015-2018 Audi Q3 Fender: Replacement, Part Numbers, and Side Marker Light Explained
This guide covers everything you need to know about replacing your 2015-2018 Audi Q3 fender, including the critical details about side marker lights and non-reusable wheel moldings.
- The fender for a North American 2015-2018 Q3 does NOT have a side marker light hole; the light is in the bumper.
- The plastic wheel opening molding is a one-time-use part and MUST be replaced along with the fender.
- When buying used, check for hidden rust on the inner wheel arch lip and signs of previous body filler repairs.
- Part numbers are side-specific: 8U0821105 for the left (driver) side and 8U0821106 for the right (passenger) side.
Symptoms of a Damaged Fender
Symptoms of a failing or damaged fender are almost always visual or audible. Because it's an exterior body panel, damage is typically easy to spot.
- Visible Damage: This is the most common symptom and includes dents, dings, creases, deep scratches, and paint chips from collisions or impacts with road debris.
- Rust or Corrosion: Bubbling paint or visible orange/brown rust is a sign of corrosion. On the Audi Q3, pay close attention to the wheel arch lips where moisture and road salt can accumulate.
- Poor Panel Gaps: After an impact, a fender can be bent, leading to uneven gaps between the fender, hood, front bumper, and door.
- Noise: A rattling or vibrating sound while driving can indicate that the fender has come loose from its mounting points or that the inner fender liner is damaged and flapping against the tire.
Known Issues, Recalls, and TSBs
While there are no recalls specifically for the fender panel itself on the 2015-2018 Audi Q3, several related issues are important for owners to be aware of.
- NHTSA Recall 17V400000: This recall addresses a software issue that could make the side marker lights inoperative when the headlights or parking lights are on. While this isn't a fault of the fender, it's relevant because the side marker location is a key point of confusion when ordering this part.
- Other Lighting Recalls: Other campaigns were issued for issues with inoperable front turn signals on models with LED headlights (NHTSA 19V385000) and brake lights not activating with the parking brake (NHTSA 17V400000).
- Common Rust Areas: Like many vehicles, the Q3 can be susceptible to rust in areas where moisture gets trapped. Key areas to check include the inner lip of the wheel arches and along the door sills.
Pro Tip: Before assuming a lighting issue is a bad bulb, check if your vehicle's VIN has any open recalls. You can check for free on the NHTSA website.
Buying a Used 2015-2018 Q3 Fender: What to Inspect
A used OEM fender is often the best value, offering perfect factory fitment at a lower cost than a new part. However, careful inspection is key to getting a good part.
- Check for Previous Repairs: Look at the back of the fender for signs of body filler (often called "Bondo"). Run a magnet over the surface; it won't stick to areas with thick filler. Mismatched texture or sanding marks on the backside are red flags for a poor-quality repair.
- Inspect All Mounting Points: Carefully check every mounting tab and bolt hole. Ensure none are cracked, broken, or elongated from a previous impact. A fender with damaged mounting points will never align correctly.
- Look for Hidden Rust: The most critical area to inspect is the inner lip that curves into the wheel well. Peel back any rubber trim if possible and check for any signs of bubbling paint or flaking metal, which indicates the start of corrosion.
- Verify Part Numbers: Match the OEM part number to your needs. The driver's side is 8U0821105 and the passenger's side is 8U0821106.
- Confirm Side Marker Hole Status: For the North American market, the 2015-2018 Audi Q3 has its front side marker light in the bumper, not the fender. Therefore, you need a fender without a side lamp hole. Many aftermarket parts correctly list this specification. Do not buy a fender with a hole, as it is likely for a European-spec vehicle.
Cost Comparison: New vs. Used Q3 Fenders
The cost of a replacement fender can vary significantly based on whether you choose new OEM, aftermarket, or used OEM. Remember to factor in the cost of painting, which can add $200-$500.
| Part Type | Estimated Cost (Part Only) | Notes |
|---|---|---|
| New OEM | $440 - $680 | Purchased from an Audi dealer. Guarantees perfect fitment but is the most expensive option. Arrives unpainted. |
| New Aftermarket | $95 - $225 | Made by third-party manufacturers. Fitment can sometimes be inconsistent. Arrives unpainted (primed). |
| Used OEM | $150 - $350 | Salvaged from a donor vehicle. Offers OEM fitment at a lower price. May come in the correct color, saving on paint costs. |
| Shop Labor (Installation) | $150 - $300 | This is for installation only and does not include painting. |
Fender Replacement Overview & Difficulty
Replacing the fender on a 2015-2018 Audi Q3 is a moderately difficult job that a skilled DIYer can accomplish with basic tools.
- Difficulty: 3/5
- Estimated Time: 1.5 - 2.5 hours
- Tools Needed: Socket set, wrenches, Torx bits, trim removal tools, car jack, and jack stands.
The general process involves: opening the hood and front door for access, removing the front wheel, detaching the plastic fender liner, loosening the front bumper cover on that side, and then unbolting the fender itself. Bolts are typically located at the top of the engine bay, inside the door jamb, and behind the bumper cover.
Warning: The wheel opening molding—the plastic trim piece that lines the fender arch—is a one-time-use part. It cannot be safely removed and reinstalled. You must purchase a new molding for the replacement fender.
Part Numbers and Compatibility
Ensuring you have the correct part number is essential for a successful repair. These fenders fit all trims of the Audi Q3 for model years 2015, 2016, 2017, and 2018.
| Side | OEM Part Number | Aftermarket (Partslink) Number |
|---|---|---|
| Left (Driver) | 8U0821105 / 8U0-821-105 | AU1240135 |
| Right (Passenger) | 8U0821106 / 8U0-821-106 | AU1241135 |
Related parts you may need include the fender liner (inner panel) and the wheel opening molding, which are sold separately.
Frequently Asked Questions (FAQ)
Does the 2015-2018 Audi Q3 fender have a hole for the side marker light?
No, for North American models, the fender should not have a side marker light hole. The front side marker for the US-spec Q3 is located in the front bumper cover, not the fender. Fenders sold with a side light hole are typically for European models which use a turn signal repeater in that location.
Can I reuse my old wheel opening molding?
No. Audi specifies that the wheel opening molding (the plastic arch trim) is a one-time-use part and cannot be reused. You must purchase a new one when replacing the fender.
Do I need to paint a used fender?
It depends. If you can find a used OEM fender from a vehicle with the same factory paint code, you may be able to install it without painting. However, due to potential fading on the rest of your car, even a color-matched part might not be a perfect match. New OEM and new aftermarket fenders always come primed and require painting.
What is the difference between the left and right fender?
The fenders are side-specific and not interchangeable. The left side (driver's side in the US) is part number 8U0821105, and the right side (passenger's side) is 8U0821106.
Technical Specifications
OEM Part Numbers: 8U0-821-105 8U0821105 8U0821105A 8U0-821-106 8U0821106 8U0821106A
Material: Steel. Finish: Primed (unpainted).
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Audi Q3: