Walker
Quiet-Flow SS

Walker 21918 Exhaust Muffler

Brand Walker 21918
Muffler Type Reflection
Finish Natural
Universal Or Specific Fit Specific
Shape Oval
Grade Type Regular
Inlet Inside Diameter 2.25
Body Width 11
Inlet Quantity 1
Reversible No
Tunable No
Overall Length 24.375
Body Height 5.5
Body Length 17
Body Material Stainless steel
Inlet 1 Inside Diameter 2.25
Inlet 1 Type Pipe connection
Inlet Configuration Offset
Inlet Offset 3.75
Inlet Type Pipe connection
Outlet 1 Outside Diameter 2.75
Outlet 1 Type Dual tips
Outlet 2 Outside Diameter 2.75
Outlet Configuration Dual
Outlet Outside Diameter 2.75
Outlet Quantity 2
Outlet Type Dual tips
Product line Quiet-Flow SS
Fits Ford · 4 vehicles

100% stainless-steel construction. Resists corrosion and keeps its finish looking clean.

Precision fit. Installs cleanly with an OE-style sound profile.

Reflection muffler design. Delivers superior flow in a compact oval body.

Cross-references AP Exhaust 30020, AP Exhaust 78286 and Four Seasons 54933 for the same application. See all 4.

$122.88Free shipping
In stock · usually ships same day before 1pm CST
Step 1 — Confirm fitment
Free return shipping if it doesn't fit when you check fitment here first.
Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
Step 2 — Quantity
Order total $122.88
Free shipping to the continental U.S.
Free returns within 60 days if it doesn't fit when fitment is verified.

Walker Quiet-Flow SS Muffler for Ford Flex

Walker Quiet-Flow SS 21918 is a specific-fit exhaust muffler built with 100% stainless-steel construction for corrosion resistance and long-term service. It is engineered for the 2009-2012 Ford Flex and uses an OE-style sound profile with precision fit and smooth exhaust flow.

Key Features

  • Specific-fit exhaust muffler for 2009-2012 Ford Flex
  • 100% stainless-steel body material with natural finish
  • Oval reflection-style muffler design
  • 2.25-inch inlet inside diameter with offset inlet configuration
  • Dual 2.75-inch outlet tips and dual outlet configuration
  • Overall length: 24.375 inches; body length: 17 inches
  • Walker Quiet-Flow SS 21918 for OE-style sound and fit

Product Details

The Walker Quiet-Flow SS line focuses on stainless-steel construction, accurate fitment, and controlled exhaust tone for domestic and import vehicles. This Quiet-Flow SS muffler is shaped as an oval reflection-type unit and is sized for direct replacement on the Ford Flex platform. The 2.25-inch pipe connection inlet, offset inlet layout, and dual-tip outlet arrangement support a factory-style exhaust configuration while maintaining a clean, finished appearance at the rear of the vehicle. Walker 21918 is also cross-referenced with AP Exhaust 30020 and Four Seasons 54933 for the same application.

Common Issues It Can Address

  • Rust or corrosion in the original muffler housing
  • Exhaust noise that has increased from internal muffler wear
  • Poor fit from a replacement muffler that does not match the factory layout
  • Reduced exhaust flow caused by a damaged or restricted muffler
  • Visible deterioration of the rear exhaust section on a Ford Flex

Installation Notes and Tips

Compatible with 2009-2012 Ford Flex models listed in the fitment data. Verify inlet and outlet dimensions, offset configuration, and overall length against the existing exhaust before installation. If the vehicle uses a welded assembly, replace all required parts in the system to maintain proper alignment and sealing. Walker 21918 is a specific-fit muffler, so matching the factory exhaust routing is important for correct installation.

Quality Assurance

Walker Quiet-Flow SS mufflers are built with stainless-steel construction and are positioned for OE-style sound and precision fit. Fitment for this part includes 2009-2012 Ford Flex, and the product line is backed by a limited lifetime warranty noted in the fitment data.

This part fits 4 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelLitersCylindersNotes
2012FordFlex3.5LV6Premium; Limited Lifetime Warranty; If welded assembly, replace all required parts; Quiet-Flow SS
2011FordFlex3.5LV6Premium; Limited Lifetime Warranty; If welded assembly, replace all required parts; Quiet-Flow SS
2010FordFlex3.5LV6Premium; Limited Lifetime Warranty; If welded assembly, replace all required parts; Quiet-Flow SS
2009FordFlex3.5LV6Premium; Limited Lifetime Warranty; If welded assembly, replace all required parts; Quiet-Flow SS
Directly replaces or cross-references 4 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
AP Exhaust — 30020AP Exhaust — 78286Four Seasons — 54933Four Seasons — 55684