Rolls Royce Cullinan RR31 Exhaust Muffler 8685587 8685587

For the Rolls-Royce Cullinan (RR31), the part number 8685587 refers to the OEM Center Muffler (Silencer) assembly. This component is part of the sophisticated, valved exhaust system designed to maintain the Cullinan’s near-silent operation under normal driving while allowing for a more pronounced V12 note when the “Low” or “Sport” modes are engaged.

1. Technical Overview

Part Number: 8685587 (Secondary reference: 18308685571 / 8685571)
Location: Middle section of the exhaust system, situated between the downpipes/catalytic converters and the rear muffler.
Compatibility: * Cullinan Series I (2018–2024) * Cullinan Black Badge
- Cullinan Series II (2025–2026)
Material: High-grade, heat-resistant stainless steel with brushed aluminum-style heat shielding.

2. Why Replace the 8685587?

While stainless steel is durable, there are two common reasons for sourcing this part in 2026:

Exhaust Valve Failure: The internal flap mechanisms in the center/rear section can occasionally rattle or seize due to carbon buildup or actuator failure. This results in a “Service Exhaust System” or “Drivetrain Malfunction” warning.
Structural Damage: Given the Cullinan’s “Off-Road” mode, this center section is the most vulnerable to ground strikes or debris when the air suspension is at its maximum height.