2018-2020 McLaren 720S Fuel Tank Corrosion: The Recall and Risks You Must Know
A critical guide to the official recall for fuel tank corrosion on the 2018-2020 McLaren 720S, its symptoms, and what to check before buying a used part.
- The most critical issue is NHTSA Recall 20V-231, where a foam pad under the tank traps moisture and corrodes the tank, causing fuel leaks.
- A fuel smell is a critical symptom of this recall issue and indicates a fire risk; the vehicle should not be driven.
- The official fix is to remove the foam pad and, if corrosion is found, replace the entire fuel tank.
- When buying a used tank, you must inspect the bottom surface for any signs of corrosion or pitting and verify the recall was performed on the donor car.
Known Issues: NHTSA Recall 20V-231 - Fuel Tank Corrosion
The most critical issue affecting the fuel system on 2018-2020 McLaren 720S models is not a failure of the mounting brackets, but a design flaw that can cause the fuel tank itself to corrode and leak. This prompted McLaren to issue a voluntary safety recall (NHTSA Campaign Number: 20V231000).
The problem stems from a Noise, Vibration, and Harshness (NVH) foam pad installed underneath the fuel tank. This foam pad was found to trap and hold moisture, such as salt water from treated roads, directly against the surface of the aluminum fuel tank. Over time, this constant contact with moisture can cause the tank to corrode, leading to the formation of microscopic holes, or 'micro-porations'. These holes can allow fuel vapor or liquid fuel to leak out, creating a significant fire hazard.
Warning: A fuel leak of any kind increases the risk of a vehicle fire. The primary symptom of this issue is a persistent fuel smell. If you smell fuel in or around your vehicle, it should be inspected immediately by a qualified technician.
The official remedy for this recall involves dealers removing the NVH foam pad from underneath the fuel tank. During this service, the technician inspects the fuel tank for any signs of corrosion. If corrosion is present or a leak is confirmed, the fuel tank is replaced at no cost to the owner. This recall affected 2,008 McLaren 720S vehicles in the United States.
Symptoms of Fuel Tank System Failure
1. Fuel Smell
A distinct smell of gasoline inside or outside the vehicle is the most direct symptom of the corrosion issue identified in the recall. As the tank develops micro-porations from corrosion, fuel vapors escape. This smell may be more noticeable after the car has been sitting or in an enclosed space like a garage. Do not ignore this symptom, as it indicates a fuel leak.
2. Rattling or Clunking Noises
While not related to the recall, a rattling, clunking, or thumping sound coming from the rear of the vehicle, especially when driving over bumps or during sharp turns, can indicate that the fuel tank mounting straps or brackets are loose or have failed. This allows the tank to shift and hit against the chassis or other components. This is a serious safety issue that requires immediate inspection.
3. Visibly Sagging Fuel Tank
A visual inspection underneath the vehicle may reveal that the fuel tank is hanging lower than it should or appears tilted to one side. This is a clear sign that one or more of the mounting straps or brackets has broken or detached, and the tank is no longer secure. Driving the vehicle in this condition is extremely dangerous.
Buying a Used Fuel Tank or Assembly
Due to the high cost of new OEM parts, a recycled fuel tank assembly can be a viable option. However, given the known corrosion issue, careful inspection is mandatory.
Key Inspection Points for a Used Part:
- Verify Recall Completion: If purchasing a complete vehicle, use the VIN to check with a McLaren dealer or the NHTSA database to ensure recall 20V-231 has been completed. This confirms the problematic foam pad has been removed.
- Inspect the Bottom Surface: The corrosion occurs on the underside of the tank where the foam pad was located. Thoroughly inspect this entire surface for any pitting, white chalky oxidation, or signs of previous repairs. Any evidence of corrosion is a major red flag.
- Check for Physical Damage: Examine the entire tank for dents, deep scratches, or cracks that could have occurred from road debris or improper handling after removal. Pay close attention to the corners and seams.
- Examine Mounting Points: Inspect the areas where the mounting straps or brackets make contact. Ensure there are no cracks or stress marks. For the brackets themselves, check for any cracks in the welds or bends in the metal.
- Confirm Part Numbers: Whenever possible, match the part number to the original. A known part number for a 720S fuel tank assembly is 14KA060CP. Compatibility is critical on a vehicle like the 720S.
Pro Tip: For this specific vehicle, a used OEM part from a reputable seller who can provide the history of the donor car (including recall status) is strongly preferred. There are no reliable aftermarket alternatives for the fuel tank or its structural mounting components.
Replacement Difficulty & Labor
- Difficulty Rating: 5 out of 5 (Professional Technician Recommended)
- DIY Feasible: No
Replacing the fuel tank on a McLaren 720S is a complex and labor-intensive job that should not be attempted by a DIY mechanic. The process involves safely draining all fuel, lifting the vehicle, disconnecting sensitive fuel lines, electrical connectors, and the filler neck, and supporting the tank while removing the mounting straps. Given the fire risk and the complexity of the vehicle's systems, this repair is best left to technicians with specific experience on McLaren models.
Cost Comparison
Pricing for McLaren parts can be high, and labor at specialized shops reflects the complexity of the work.
| Part/Service | Estimated Cost |
|---|---|
| New OEM Fuel Tank Assembly | $4,000 - $6,000+ (Part only) |
| Used OEM Fuel Tank Assembly | $1,500 - $3,000+ (Depending on condition and included components) |
| Shop Labor for Replacement | $1,500 - $2,500+ (Estimate, highly dependent on shop rates) |
| New Aftermarket | Not Available |
Frequently Asked Questions (FAQ)
Is it safe to drive my 720S if I smell fuel?
No. A fuel smell indicates a leak, which is a serious fire hazard. You should not drive the vehicle. Have it towed to a qualified service center for immediate inspection.
How do I know if the recall work has been done on my car?
You can contact any authorized McLaren dealership with your vehicle's VIN. They can look up the service history and confirm if recall 20V-231 has been completed. You can also check the NHTSA recall website.
The recall is about a foam pad. Why would I need to replace the whole tank?
The foam pad itself is just the cause of the problem. The recall service involves removing the pad to prevent future issues. However, if the pad has already held moisture against the tank long enough to cause corrosion or leaks, the tank itself is compromised and must be replaced for safety.
Are the fuel tank mounting brackets a common failure point?
No, there are no widespread documented issues, recalls, or TSBs related to the failure of the fuel tank mounting brackets or straps on the 2018-2020 McLaren 720S. The primary documented issue in this area is the corrosion of the tank itself.
Technical Specifications
OEM Part Numbers: 14KA060CP
The fuel tank is made of aluminum. The recall issue is specific to vehicles originally equipped with a noise-insulating foam pad on the underside of the tank.
We Have This Part in Stock
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.
- McLaren 720S:
- 🛍️ Shop This Part
- Known Issues: NHTSA Recall 20V-231 - Fuel Tank Corrosion
- Symptoms of Fuel Tank System Failure
- 1. Fuel Smell
- 2. Rattling or Clunking Noises
- 3. Visibly Sagging Fuel Tank
- Buying a Used Fuel Tank or Assembly
- Key Inspection Points for a Used Part:
- Replacement Difficulty & Labor
- Cost Comparison
- Frequently Asked Questions (FAQ)
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