Sierra 18-4009 Manifold Front Plate, Replaces Mercury Marine 60252A2, Fits Port and Starboard Exhaust Manifolds

The Sierra 18-4009 is a front (end) plate for marine exhaust manifolds, designed to mount to the front of the manifold casting and seal the internal water and exhaust passages. It is built to meet or exceed original equipment quality and is cross-referenced to Mercury Marine part number 60252A2, making it a direct equivalent for engines and manifold assemblies that call for that OEM plate.

This front plate is used with Sierra exhaust manifolds 18-1958-1 and 18-1962-1, and fits both the port and starboard versions of those manifolds, so a single part number covers either side of the engine. It pairs with the Sierra 18-8512 mounting kit, which supplies the matching 18-2832-1 front/end plate gasket needed for a complete, sealed installation. The plate has a machined finish for a consistent, flat sealing surface against the manifold casting.

Because the manifold's internal water jacket runs past the front plate, a worn, cracked, warped, or corroded original plate is a common source of coolant leaks and can allow raw water to escape or air to enter the cooling passages. Replacing the 18-4009 along with its mating gasket restores a tight seal at this joint and is a routine step when servicing or rebuilding the 18-1958-1 or 18-1962-1 manifold.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-4009
• Product Type: Exhaust Manifold Front/End Plate
• OEM Cross Reference: Mercury Marine 60252A2
• Compatible Manifolds: 18-1958-1, 18-1962-1 (Port & Starboard)
• Compatible Mounting Kit: 18-8512 (includes 18-2832-1 gasket)
• Finish: Machined
• Weight: 1.41 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• UPC: 030999563200

Fitment

• Sierra Exhaust Manifolds 18-1958-1 and 18-1962-1, Port and Starboard
• Used with Sierra Mounting Kit 18-8512

Replaces (OEM)

• Mercury Marine 60252A2

Frequently Asked Questions

What does the Sierra 18-4009 fit? The Sierra 18-4009 front plate is used with exhaust manifolds 18-1958-1 and 18-1962-1, and it fits both the port and starboard versions of those manifolds.

Is the 18-4009 the same as Mercury Marine 60252A2? Yes, the Sierra 18-4009 is cross-referenced to Mercury Marine part number 60252A2 and is built to meet or exceed original equipment quality.

Does this plate fit both port and starboard manifolds? Yes. The 18-4009 is designed for use with both the port and starboard 18-1958-1 and 18-1962-1 manifolds, so one part number works on either side.

What gasket do I need with the 18-4009 front plate? The front plate pairs with the 18-2832-1 front/end plate gasket, which is included in the Sierra 18-8512 mounting kit.

How much does the 18-4009 weigh? The Sierra 18-4009 front plate weighs 1.41 pounds.

What is the mounting kit used with this part? The 18-4009 uses the Sierra 18-8512 mounting kit, which includes the matching 18-2832-1 gasket for installation.

What finish does the 18-4009 have? The plate has a machined finish for a flat, consistent sealing surface against the exhaust manifold casting.

Why would I need to replace the exhaust manifold front plate? A worn, cracked, or corroded front plate can leak at the manifold's water jacket; replacing the 18-4009 along with its gasket restores a proper seal during manifold service or rebuilds.

Is the Sierra 18-4009 an OEM or aftermarket part? The 18-4009 is a Sierra aftermarket replacement front plate, manufactured to meet or exceed the quality of the original Mercury Marine 60252A2 it replaces.

What are the dimensions of the 18-4009 front plate? The Sierra 18-4009 measures 0.39 x 0.39 x 0.39 inches.

Does the 18-4009 come with mounting bolts? No, mounting bolts are supplied separately as part of the Sierra 18-8512 mounting kit, not with the 18-4009 plate alone.