Walker 21678 Exhaust Muffler - Left

Walker Quiet-Flow SS Muffler for Honda Pilot

Walker Quiet-Flow SS Part Number 21678 is a specific-fit exhaust muffler built for the left side of select Honda Pilot applications. It uses stainless-steel body construction, an oval shape, and an OE-style sound profile to support a direct replacement for the factory muffler on 2009-2015 Honda Pilot models.

Key Features

• Specific-fit exhaust muffler for select Honda Pilot applications
• 100% stainless-steel body construction for corrosion resistance
• Oval muffler design with reflection-style internal construction
• Offset inlet and offset outlet configuration
• 1.75-inch inlet inside diameter and 2.25-inch outlet outside diameter
• Reversible design for installation flexibility where the application allows
• Walker Quiet-Flow SS product line focuses on precision fit, flow, and OE-style sound

Product Details

This Walker exhaust muffler is part of the Quiet-Flow SS line, a stainless-steel muffler family developed for domestic and import vehicles where a direct-fit replacement is needed. Part Number 21678 is engineered for the left position on 2009-2015 Honda Pilot models and is built with a stainless-steel body and aluminized finish. The oval body measures 11 inches wide, 5.5 inches high, and 14 inches long, with an overall length of 28.5 inches. The inlet uses a 1.75-inch pipe connection with a 3.75-inch offset, and the outlet uses a 2.25-inch tip connection with an offset configuration.

This part cross-references AP Exhaust 30031 for the same application. It also cross-references Walker Exhaust 54839 for the same application.

Common Exhaust Issues It Can Address

• Rust-through or corrosion in the original muffler body
• Exhaust noise increase from a damaged internal muffler structure
• Fitment problems when replacing a worn left-side Honda Pilot muffler
• Loss of OE-style exhaust tone after factory muffler deterioration
• Need for a direct replacement with stainless-steel construction

Installation Notes and Tips

Fits 2009-2015 Honda Pilot, left. Verify inlet and outlet orientation, offset dimensions, and pipe diameter before installation. If the original system uses a welded assembly, replace all required exhaust components during service to maintain proper alignment and sealing. Confirm clearance around the oval body and tip outlet before final tightening.

Quality Assurance

Walker Quiet-Flow SS mufflers are built with 100% stainless-steel construction and are positioned as precision-fit replacement parts with OE-style sound characteristics. Part Number 21678 is backed by Walker’s Quiet-Flow SS product design for broad-market exhaust replacement applications.