57-865615Q06 Serpentine Belt for MerCruiser Alpha Bravo | JLM Marine

Serpentine Belt for MerCruiser Alpha & Bravo – Direct Replacement for 57-865615Q06

This high-quality aftermarket serpentine belt is engineered for MerCruiser stern drive and inboard engines equipped with Alpha and Bravo drives. Designed to meet OEM specifications, it fits select 5.0L, 6.2L, 350, 454, 7.4L, and 502 Mag MPI engines with specific accessory configurations including power steering, closed cooling, and high-mount alternators.

Direct Replacement for: 57-865615Q06, 57-865615-006, 57-8638766, 57-8610491, and multiple aftermarket equivalents including Sierra 18-15102. Always verify your original OEM part number before ordering, as similar engines with different accessories may require different belts.

• Fits MerCruiser engines with power steering, closed cooling, and high-mount alternator configurations
• Compatible with 5 3/4 inch pulley systems on select models
• Manufactured to OEM specifications for reliable performance

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Important: Please be sure to match up the OEM part number of your belt. Similar engines with different accessories may require different belts.

Technical Specifications

Package Contents

• 1 × Serpentine Belt (57-865615Q06)

Installation Guide

1. Disconnect the battery: Always disconnect the negative battery terminal before beginning work to prevent electrical shorts.
2. Locate the belt routing diagram: Reference your engine's belt routing decal or service manual to understand the correct path around pulleys.
3. Release tension on the old belt: Use a wrench or belt tensioner tool to rotate the tensioner pulley and relieve tension. Remove the old belt from all pulleys.
4. Inspect pulleys and tensioner: Check all pulleys for wear, cracks, or damage. Replace any worn components before installing the new belt.
5. Route the new belt: Following the routing diagram, thread the new serpentine belt around each pulley in the correct sequence.
6. Apply tension: Use the tensioner tool to rotate the tensioner pulley, then slip the belt onto the final pulley. Release the tensioner slowly to apply proper tension.
7. Verify alignment: Ensure the belt is properly seated in all pulley grooves and aligned correctly—no twists or misalignment.
8. Reconnect the battery: Reconnect the negative battery terminal securely.
9. Start the engine and check: Run the engine briefly and listen for unusual noises. Observe the belt to confirm it runs smoothly without slipping or vibrating.
10. Re-check tension after break-in: After the first few hours of operation, inspect belt tension and re-adjust if necessary.

Troubleshooting & FAQ

Q: How do I confirm this belt fits my MerCruiser engine?
A: Match your engine's OEM part number (found on your existing belt or in your service manual) with the cross-reference list above. Verify your engine model, year, serial number range, and accessory configuration (power steering, closed cooling, high-mount alternator) match the compatibility table. Similar engines with different accessories may require different belts.

Q: My engine model is listed, but I have a different pulley size. Will this belt work?
A: No. Pulley diameter and accessory configuration determine belt length and routing. This belt is designed for engines with a 5 3/4 inch pulley on select models and specific accessory setups. Always confirm the exact OEM part number before ordering.

Q: How often should I replace the serpentine belt?
A: MerCruiser recommends inspecting the serpentine belt annually and replacing it every 3–5 years or sooner if you notice cracking, fraying, glazing, or squealing. High-use or harsh marine environments may require more frequent replacement.

Q: What are the signs that my serpentine belt is failing?
A: Common symptoms include squealing or chirping noises (especially during startup or acceleration), visible cracks or fraying on the belt surface, loss of power steering assist, alternator/charging issues, or engine overheating due to water pump failure. Replace the belt immediately if any of these signs appear.

Q: Can I install this belt myself, or do I need a mechanic?
A: If you have basic mechanical skills and the proper tools (including a belt tensioner tool), you can install this belt yourself by following the routing diagram and installation steps. However, professional installation is recommended to ensure correct tension, alignment, and safety.

Q: Is this an OEM belt or an aftermarket replacement?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.