Sierra 18-15116 Serpentine Belt, Replaces 57-861758/57-861758Q, Fits Mercruiser 4.3L Alpha 1996-99

The Sierra 18-15116 is a serpentine belt engineered for Mercruiser 4.3L Alpha sterndrive engines built in the 1996-99 model years within the OF803000-OL618999 serial number range (foothole positions 2 and 6). It is constructed from polychloroprene rubber and polyester fiber tensile members, giving the belt the tensile strength and flexibility needed to drive engine accessories under continuous marine duty. The belt is built with oil resistance and temperature stability standard, so it holds up against the heat cycling, oil exposure, and vibration typical of an inboard/outboard engine compartment.

This belt measures 13/16 inch wide and 86.75 inches long, matching the OEM Mercruiser dimensions for this application. It is manufactured to be correct in fit, form, and function as a direct replacement for the original equipment belt, cross-referencing to Mercruiser part numbers 57-861758 and 57-861758Q. Boat owners and marine technicians use it as a routine maintenance replacement when an aging serpentine belt shows cracking, glazing, or stretch, or as a preventive swap during scheduled engine service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-15116
• Belt Style: Serpentine
• Width: 13/16 inch
• Length: 86.75 inches
• Material: Polyester, Rubber
• Color: White
• Weight: 0.5 pounds
• UPC: 808282145507
• OEM Cross-Reference: 57-861758, 57-861758Q

Fitment

• Mercruiser 4.3L Alpha, 1996-99, serial number range OF803000-OL618999, foothole positions 2 and 6

Replaces (OEM)

• 57-861758
• 57-861758Q

Frequently Asked Questions

What engines does the Sierra 18-15116 serpentine belt fit? This belt fits Mercruiser 4.3L Alpha sterndrive engines built in the 1996-99 model years, specifically within the serial number range OF803000-OL618999, at foothole positions 2 and 6.

What are the OEM cross-reference numbers for this belt? Sierra 18-15116 replaces Mercruiser part numbers 57-861758 and 57-861758Q, so either OEM number can be used to confirm the correct match.

What size is the 18-15116 serpentine belt? It measures 13/16 inch in width and 86.75 inches in length.

What material is the belt made from? The 18-15116 belt is made of polychloroprene rubber with polyester fiber tensile members, giving it oil resistance and temperature stability for marine engine use.

Is this a genuine Mercruiser part or an aftermarket replacement? The 18-15116 is a Sierra aftermarket belt manufactured to be OEM quality and correct in fit, form, and function as a replacement for Mercruiser 57-861758 and 57-861758Q.

How much does the 18-15116 belt weigh? It weighs 0.5 pounds.

What color is the Sierra 18-15116 belt? It is white.

Will I need any special tools to install this belt? The 18-15116 is a standard serpentine belt for a Mercruiser 4.3L Alpha engine, and installation follows the same belt routing and tensioner release procedure as the original equipment belt it replaces.

Does the foothole position matter when ordering this belt? Yes, the 18-15116 is specified for foothole positions 2 and 6 on the Mercruiser 4.3L Alpha, 1996-99, serial range OF803000-OL618999, so confirming the foothole position helps ensure correct fitment.

What is included when I order this part? You receive one Sierra 18-15116 serpentine belt.