Sierra 18-0403 Intake Gasket Kit, Replaces Mercury Marine 27-52571, Fits MCM 370/400/325/454/502 Mag & MIE 82L 1978-1997

The Sierra 18-0403 Intake Gasket Kit is a complete gasket set engineered to seal the intake manifold on select Mercury Marine sterndrive and inboard engines. This kit is built as a direct equivalent to the original Mercury Marine intake gasket, giving boat owners and marine technicians a reliable way to restore a proper seal at the intake manifold without sourcing a discontinued or hard-to-find factory part.

The kit includes the full complement of gaskets needed for a complete intake gasket replacement in a single package, finished in white. It is designed for use on MCM 370, 400, 325, 454, and 502 Mag engines, as well as the 74L Bravo II and MIE 82L, covering the 1978-1997 production span for these applications. Installing a fresh intake gasket kit at this interval helps prevent coolant, oil, or intake air leaks caused by a hardened or degraded factory gasket.

At 0.61 pounds, the 18-0403 kit ships as a compact, ready-to-install package. Because it carries the Sierra 18-0403 part number and cross-references Mercury Marine 27-52571, it can be ordered with confidence as a fit-for-purpose replacement rather than a generic aftermarket substitute.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0403
• Product Type: Intake Gasket Kit
• Included Components: Intake Gasket Kit
• Color: White
• Weight: 0.61 pounds
• UPC: 808282200602
• OEM Cross Reference: 27-52571

Fitment

• MCM 370, 400, 325, 454, 502 Mag
• 74L Bravo II
• MIE 82L
• 1978-1997

Replaces (OEM)

• 27-52571

Frequently Asked Questions

What engines does the Sierra 18-0403 intake gasket kit fit? The 18-0403 kit fits MCM 370, 400, 325, 454, and 502 Mag engines, along with the 74L Bravo II and MIE 82L, covering the 1978-1997 model years for these applications.

What OEM part number does this gasket kit replace? This kit cross-references Mercury Marine OEM number 27-52571, so it can be ordered as a direct equivalent to that factory part under Sierra part number 18-0403.

How much does the 18-0403 intake gasket kit weigh? It weighs 0.61 pounds as packaged.

What color is the Sierra 18-0403 gasket kit? It is finished in white.

Is this a complete gasket set or a single gasket? The 18-0403 is a kit that includes the full set of intake gaskets needed for the job, not a single individual gasket.

Will this kit work on any Mercury Marine engine? No, the 18-0403 is designed specifically for the MCM 370, 400, 325, 454, and 502 Mag engines and the 74L Bravo II and MIE 82L from 1978-1997; it is not a universal fit across all Mercury Marine engines.

Is the Sierra 18-0403 kit genuine Sierra or a generic aftermarket part? It is a genuine Sierra-branded part, sold under Sierra part number 18-0403, engineered as a cross-reference match to Mercury Marine 27-52571 rather than a generic substitute.

When should I replace the intake gasket with this kit? An intake gasket kit like the 18-0403 should be installed any time the intake manifold is removed or when signs of a leaking intake seal, such as coolant or oil seepage at the manifold, are present.

Does the 18-0403 kit include everything needed for installation? Yes, the kit's included components consist of the intake gasket set required for the job, packaged together as the 18-0403.

What is the UPC for the Sierra 18-0403 intake gasket kit? The UPC for this product is 808282200602.

Does the 74L Bravo II use the same intake gasket kit as the MCM engines? Yes, the Sierra 18-0403 kit covers the 74L Bravo II in addition to the MCM 370, 400, 325, 454, 502 Mag, and MIE 82L engines.