Sierra V-Belt 18-15490, Replaces Mercury Marine 57-816295T, for Mercruiser 4.3L Gen II and 4.3LX Engines

The Sierra 18-15490 V-Belt is a white rubber drive belt engineered for Mercruiser 4.3L engine applications, including the 4.3L Gen II (2bbl) and 4.3LX (4bbl) engine builds. It is built with a cogged profile molded to precise engineering tolerances, which improves belt flexibility while keeping the cord structure well supported through each rotation. Inside the belt, high-strength synthetic cords resist shock loading and hold a low-stretch profile, so the belt maintains uniform performance over its service life instead of loosening prematurely. The open cog design also increases the surface area exposed to air circulation, helping keep the belt running cooler and reducing heat buildup during extended operation. Rubber edges are formulated to maintain positive, no-slip contact inside the pulley grooves, which keeps energy transfer consistent and reduces the chance of belt slip under load. A special rubber compound section works together with the internal cords to ensure load forces are transferred smoothly and evenly rather than in sudden jolts. Measuring an effective length of 52 1/2 inches with a top width of 29/64 inch, this V-belt is designed as a direct fit for Mercruiser 4.3L Gen II and 4.3LX engines within the serial number ranges noted below.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-15490
• Product Type: V-Belt
• Color: White
• Material: Rubber
• Effective Length: 52 1/2 inches
• Top Width: 29/64 inch
• Weight: 0.25 pounds
• OEM Cross-Reference: Mercury Marine 57-816295T

Fitment

• Mercruiser 4.3L Gen II (2bbl), 262 cid, V6, serial number range OD714107-OF802999
• Mercruiser 4.3LX (4bbl), 262 cid, V6, serial number range OB775130-OD714369

Replaces (OEM)

• Mercury Marine 57-816295T

Frequently Asked Questions

What engines does the Sierra 18-15490 V-belt fit? The Sierra 18-15490 V-belt fits Mercruiser 4.3L Gen II (2bbl) engines within serial number range OD714107-OF802999 and Mercruiser 4.3LX (4bbl) engines within serial number range OB775130-OD714369.

Is the 18-15490 belt the same as Mercury Marine 57-816295T? Yes, Sierra part 18-15490 is a direct cross-reference to Mercury Marine part 57-816295T for the same Mercruiser 4.3L engine applications.

What are the dimensions of this V-belt? The 18-15490 V-belt has an effective length of 52 1/2 inches and a top width of 29/64 inch.

How much does the Sierra 18-15490 V-belt weigh? This V-belt weighs 0.25 pounds.

What material is the 18-15490 V-belt made from? It is made from rubber, with high-strength synthetic cords inside the belt body to resist shock loading and stretch.

What color is the Sierra 18-15490 belt? The 18-15490 V-belt is white.

Why does this belt have a cogged design? The cogs on the Sierra 18-15490 are molded to precise engineering tolerances to improve flexibility and maintain cord support, and the open cog profile increases air circulation to help keep the belt cool and reduce heat buildup.

Will this belt slip on the pulley over time? The rubber edges of the 18-15490 are designed to maintain positive, no-slip contact with the pulley grooves for reliable, consistent energy transfer.

Is the 18-15490 a genuine Sierra part or an aftermarket copy? 18-15490 is the Sierra manufacturer part number itself, not an aftermarket copy of another brand's belt.

Does the 18-15490 belt work with the 4.3LX 4bbl engine specifically? Yes, one of its two listed applications is the Mercruiser 4.3LX (4bbl) engine, within serial number range OB775130-OD714369.

What is included when I order this part? Ordering Sierra 18-15490 includes one V-belt sized for the Mercruiser 4.3L Gen II and 4.3LX engine applications listed for this part number.