Dorman 674-522XD Exhaust Manifold - Left

Dorman 674-522XD Exhaust Manifold

The Dorman 674-522XD exhaust manifold is a direct-fit replacement for the left side on a wide range of Chevrolet, GMC, Cadillac, and Hummer applications. Built from ductile iron with a black finish, it is engineered to match the original fit and function while supporting a complete exhaust repair with included gaskets and downpipe hardware.

Key Features

• Ductile iron construction for strength and heat resistance
• Black finish with round ports and a 21 mm collector port diameter
• Standard replacement grade for OE-style fitment
• Heat shield included
• Mounting hardware and gaskets included
• No oxygen sensor port
• 9 mounting holes for specified vehicle applications

Detailed Description

This Dorman exhaust manifold is precision-engineered to match the original manifold on specified vehicles, helping restore proper exhaust routing on the left side of the engine. It is a direct replacement for many Chevrolet Silverado, GMC Sierra, Cadillac Escalade, and related full-size truck and SUV applications, including 1999-2020 coverage across multiple engine and emission configurations. Part number 674-522XD is built for standard replacement service and is designed around the original manifold layout for a straightforward repair.

This part cross-references OE numbers such as 12556078 and 12686303 for the same application.

What It Helps Fix

• Exhaust leaks at the manifold flange or gasket surface
• Cracked or warped factory manifold housings
• Broken or corroded downpipe connection hardware
• Noise from escaping exhaust gases on the left side
• Loss of exhaust sealing that can trigger drivability concerns

Installation Notes and Tips

• Verify engine configuration and emission setup before ordering, especially air pump and ceramic coating notes.
• Confirm left-side placement and match the vehicle year, make, and model exactly to the fitment list.
• Inspect the cylinder head sealing surface and exhaust fasteners before installation.
• Use the included gaskets and mounting hardware for a complete repair where specified.

Quality Assurance

Dorman manufactures this manifold as a standard replacement part engineered to match OE fit and function on specified vehicles. The ductile iron construction, included heat shield, and complete repair hardware support a reliable exhaust manifold replacement for compatible Chevrolet Silverado, GMC Sierra, Cadillac Escalade, and related applications.