Serpentine Belt – Fits MerCruiser V6/V8 Alpha & Bravo 1999–2016 (Replaces 57-865615-003, 57-865615Q03)
This serpentine belt is designed for MerCruiser V6 and V8 gasoline engines from 1999 to 2016. It is compatible with 4.3L, 5.0L, 5.7L, and 6.2L models using Alpha sterndrives with closed cooling or Bravo sterndrives with standard cooling.
It serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring a precise fit for a wide range of engine applications.
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Fuel Type Compatibility: Gasoline
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Installation Location: Engine Accessory Drive
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Function: Drives the water pump, alternator, and other critical engine accessories.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
Notes |
| Mercury / MerCruiser |
57-865615Q03 |
Current Part Number |
| Mercury / MerCruiser |
57-865615-003 |
Superseded by 57-865615Q03 |
| Mercury / MerCruiser |
57-8638763 |
Superseded by 57-865615-003 |
| Sierra |
18-15100 |
Aftermarket equivalent |
| GHmarine |
578638763 |
Aftermarket equivalent |
| UanofCn |
578656150003 |
Aftermarket equivalent |
| Heurofosh |
578638763 |
Aftermarket equivalent |
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.
| Brand |
Model |
Stroke |
Years |
OEM Part No. |
Notes |
| MerCruiser |
4.3L Alpha |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
4.3L Bravo |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
4.3L MPI Alpha/Bravo |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
5.0L Alpha |
4-Stroke |
2001-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
5.0L Bravo |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
5.0L MPI Alpha/Bravo |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
5.7L Alpha |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
5.7L Bravo |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
350 MAG Alpha |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
350 MAG Bravo |
4-Stroke |
2000-2004 |
57-865615-003 |
s/n from OL619000 |
| MerCruiser |
350 MAG MPI Alpha/Bravo |
4-Stroke |
2000-2016 |
57-865615-003 |
For engines with s/n 0M320025 through 2A455872 |
| MerCruiser |
377 MAG |
4-Stroke |
2001-2016 |
57-865615-003 |
For engines with s/n 0M320025 through 2A455872 |
| MerCruiser |
MX 6.2L MPI Bravo |
4-Stroke |
2000-2009 |
57-865615-003 |
s/n 0M300000 through 0W309999 |
| MerCruiser |
MX 6.2L MPI Horizon Bravo |
4-Stroke |
2000-2009 |
57-865615-003 |
s/n 0M300000 through 0W309999 |
Technical Specifications
| Specification |
Value |
| Product Type |
Serpentine Belt |
| Installation |
Engine Accessory Drive |
| Fuel Type |
Gasoline |
| Housing Color |
Black |
| Dimensions |
2,704 mm length (approx. 106.5 in) |
| Fitting Type |
Direct OEM Replacement |
| Warranty |
1 year manufacturer warranty |
Package Contents
- 1 x Serpentine Belt (57-865615-003/57-865615Q03)
Installation Guide
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Safety First: Disconnect the battery before beginning work to prevent accidental starting.
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Locate the Belt: Identify the serpentine belt routing around the various engine pulleys. It's helpful to take a picture or find a diagram for your specific engine model.
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Release Tension: Use a wrench or breaker bar on the automatic tensioner pulley to release the belt's tension.
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Remove Old Belt: Carefully slide the old belt off the pulleys.
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Inspect Pulleys: Before installing the new belt, spin each pulley by hand to ensure they turn smoothly and are free of debris.
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Route New Belt: Following your diagram or photo, route the new belt around the pulleys, leaving the tensioner pulley for last.
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Apply Tension: Release the tensioner back into place to apply tension to the new belt.
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Final Check: Double-check that the belt is correctly seated in the grooves of every pulley. Reconnect the battery and start the engine briefly to ensure proper operation.
Troubleshooting & FAQ
How do I confirm this belt fits my engine?
Start by checking the Part Number Cross-Reference table to see if your old belt's part number is listed. Then, consult the Compatible Engine Models table, paying close attention to your engine model, year, and serial number range (s/n) to ensure a match.
What are common signs that my serpentine belt is failing and needs replacement?
Look for visible signs of wear like cracking, glazing (a shiny surface), fraying edges, or missing chunks of ribbing. Audible signs include a persistent squealing or chirping sound from the engine bay, which often indicates the belt is slipping.
How often should I replace my serpentine belt?
There is no fixed interval, but most technicians recommend inspection during routine service and replacement every 3-5 years or as soon as signs of wear appear. A failed belt will cause critical accessories like the water pump and alternator to stop working, leading to engine overheating and loss of electrical power.
OEM vs. Aftermarket?
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.
How fast do you ship and how much does it cost?
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.
What is your warranty and return policy?
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?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.