2016-2021 McLaren 570S Undercar Shield: A Guide to Damage, Repair, and Replacement

Symptoms of a Damaged Undercar Shield

Failure of the 570S undercar shield is almost always due to physical impact. Given the vehicle's low ride height, contact with speed bumps, steep driveways, and road debris is common. Symptoms are typically straightforward:

• Scraping or Grinding Noises: The most obvious symptom is a scraping sound from underneath the car, especially over bumps. This indicates a panel is loose, sagging, or has been bent out of shape and is making contact with the road surface.
• Rattling or Banging Sounds: A loose or partially detached shield will often rattle or bang against the chassis while driving. This can be more noticeable at speed as airflow pushes the loose panel around.
• Visible Damage: A visual inspection is the best diagnostic tool. Look for cracks, large holes, missing sections, or panels that are hanging down. Pay close attention to the front splitter and the areas just ahead of the wheels.
• Increased Wind Noise: While harder to diagnose, a missing or severely damaged undertray can disrupt the car's aerodynamics, potentially leading to increased wind noise at highway speeds.

Buying a Used Undercar Shield for a McLaren 570S

For a high-performance vehicle like the 570S, sourcing a quality used OEM shield is often the most practical and cost-effective solution. Aftermarket options are typically expensive carbon fiber upgrades rather than standard replacements. Here’s what to look for when buying used:

1. Physical Inspection

Before purchasing, meticulously inspect the entire panel. The shields are typically made of aluminum.

• Check Mounting Points: This is the most critical area. Look for cracks, elongation, or breaks around every bolt hole. Damage here can make it impossible to secure the panel correctly.
• Look for Cracks and Gouges: Minor scrapes and scratches are normal for a used underbody part. However, reject any panel with significant cracks running through the body or deep gouges that compromise its structural integrity. A cracked panel may require repair.
• Inspect for Warping or Bending: Lay the shield on a flat surface to check for any major warping. A bent panel will not fit correctly and can create aerodynamic issues or noise.
• Heat Damage: Check areas near the exhaust system for any signs of melting, discoloration, or heat-related warping.

2. Compatibility and Part Numbers

The underbody is comprised of multiple sections (front, center, rear). Identify exactly which panel you need to replace. The best practice is to find the part number on your original damaged shield and match it to the used part. If you cannot find a part number, take detailed photos of your original part to compare its shape and mounting hole locations with the seller's photos.

Known part numbers include:

• Front Under Splash Shield: 13A6500CP
• Rear Under Body Splash Guard: 13A3302CP
• Under Body Skid Plate Finisher Panel: 14A0076CP

3. Why Used OEM is a Smart Choice

For a component that relies on precise fitment for both protection and aerodynamics, an Original Equipment Manufacturer (OEM) part is superior. A used OEM shield guarantees the correct material, shape, and mounting points designed by McLaren. Cheap aftermarket alternatives, if available, may not fit properly, could be made from inferior materials, and can negatively affect the car's high-speed stability.

Known Issues, Recalls, and TSBs

There are no official recalls or Technical Service Bulletins (TSBs) from McLaren or the NHTSA specifically for the undercar shields on the 2016-2021 570S. However, the panels are widely known in owner communities and by mechanics to be a common damage point simply due to the car's low ground clearance. A YouTube video shows an owner performing a DIY repair on holes in the aluminum undertray after hitting a rock, illustrating a common failure scenario.

The 570S has been subject to other recalls, including for Takata airbag inflators and potentially faulty brake banjo bolts, which should be verified as completed for any vehicle.

Cost of Replacing a McLaren 570S Undercar Shield

Pricing can vary significantly based on the specific panel needed and the source. Below are estimated costs.

Replacement Difficulty: 2/5

Replacing an undercar shield is mechanically simple, but requires the ability to safely lift the vehicle. An owner described the job as a "fairly simple when you've got the car on the ramp bolt on type job".

• Difficulty: 2 out of 5. The process involves basic hand tools.
• Estimated Time: 1.0 - 1.5 hours.
• DIY Feasible?: Yes, for individuals with a vehicle lift or high-quality jack stands and experience working safely under a car.

The basic procedure involves lifting the vehicle, locating and removing the series of bolts and clips holding the panel in place, swapping the panel, and reinstalling the fasteners. It can be helpful to have a box of assorted automotive clips on hand, as the original plastic ones can become brittle and break during removal.