Sierra 18-3864 Head Gasket, Replaces Mercury Marine 27-822844-1, Fits V-150 XR6/MAGNUM III V-6 Outboard

The Sierra 18-3864 Head Gasket is a machined outboard engine gasket built to seal the cylinder head on Mercury Marine outboard powerheads, sealing the mating surface between the cylinder head and the block to maintain compression and prevent coolant or combustion leaks. It is designed as a direct cross reference to Mercury Marine OEM part 27-822844-1, giving boat owners and marine technicians a Sierra-branded replacement for engine rebuilds, head resurfacing jobs, and routine maintenance on compatible Mercury outboards. The gasket is manufactured with a machined finish for a precise, consistent seal against the head and block surfaces.

This head gasket is intended for the Mercury V-150 (XR6/MAGNUM III) V-6 outboard powerhead. It carries UPC 030999753724 and weighs 0.17 pounds, with compact packaged dimensions of 0.39 x 0.39 x 0.39 inches. As with all Sierra parts, the 18-3864 is backed by Sierra's standard customer satisfaction warranty, and it remains an actively available part, not discontinued by the manufacturer.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3864
• Product Type: Head Gasket
• OEM Cross Reference: Mercury Marine 27-822844-1
• UPC: 030999753724
• Weight: 0.17 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• Finish: Machined
• Fitment: Mercury V-150 (XR6/MAGNUM III) V-6 outboard

Fitment

Fits the Mercury V-150 (XR6/MAGNUM III) V-6 outboard powerhead.

Replaces (OEM)

Mercury Marine 27-822844-1

Frequently Asked Questions

What Mercury outboard does the Sierra 18-3864 head gasket fit? The Sierra 18-3864 head gasket is built for the Mercury V-150 (XR6/MAGNUM III) V-6 outboard powerhead.

What OEM Mercury Marine part number does 18-3864 replace? It replaces Mercury Marine part number 27-822844-1.

Is 18-3864 the correct part number to order? Yes, 18-3864 is the Sierra manufacturer part number for this head gasket.

How much does this head gasket weigh? The Sierra 18-3864 head gasket weighs 0.17 pounds.

What are the dimensions of the 18-3864 head gasket? It measures 0.39 x 0.39 x 0.39 inches as packaged.

What material or finish does the 18-3864 head gasket have? This gasket has a machined finish for a precise seal between the cylinder head and block.

Is this a genuine Sierra part or an aftermarket copy? The 18-3864 is a genuine Sierra part, manufactured as a direct replacement for Mercury Marine 27-822844-1.

Does the Sierra 18-3864 head gasket come with a warranty? Yes, Sierra parts including the 18-3864 head gasket are covered under Sierra's customer satisfaction warranty.

What is the UPC for the Sierra 18-3864 head gasket? The UPC for this head gasket is 030999753724.

Has the 18-3864 head gasket been discontinued by the manufacturer? No, the Sierra 18-3864 head gasket is not discontinued and remains actively available.

What is the difference between the Sierra 18-3864 and OEM 27-822844-1? The Sierra 18-3864 is manufactured to the same specification as Mercury Marine OEM part 27-822844-1 and is designed as a direct replacement for it.