Serpentine Belt – Fits MerCruiser V6/V8 Alpha & Bravo Engines (Replaces 57-865615-003, 57-865615Q03)
Serpentine Belt – Fits MerCruiser V6/V8 Alpha & Bravo Engines (Replaces 57-865615-003, 57-865615Q03) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Serpentine Belt – Fits MerCruiser V6/V8 Alpha & Bravo Engines (...
Product Details
This is a high-quality aftermarket MerCruiser Serpentine Belt 57-865615Q03, designed for MerCruiser V6 and V8 (305, 350, & 377 cid) engines manufactured from 2001–2016. It is specifically compatible with Alpha sterndrive engines equipped with closed cooling systems and Bravo sterndrive engines with standard cooling, covering serial numbers from 0M320025 through 2A455872.
This belt serves as a direct replacement for MerCruiser part numbers 57-865615-003, 57-865615Q03, 57-8638763, 57-862807, and 57-862087A1.
- Engineered as a direct OEM-specification replacement for easy installation.
- Constructed from durable rubber compounds for reliable performance in marine environments.
- Drives the sea water pump and other critical engine accessories.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 57-865615Q03 |
| MerCruiser | 57-865615-003 |
| MerCruiser | 57-8638763 |
| MerCruiser | 57-862807 |
| MerCruiser | 57-862087A1 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser owners, please note the specific cooling system requirements for Alpha (closed cooling) and Bravo (standard cooling) drives mentioned in the 'Notes' column.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | V6 Alpha | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | Requires closed cooling system |
| MerCruiser | V8 (305 CID) Alpha | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | Requires closed cooling system |
| MerCruiser | V8 (350 CID) Alpha | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | Requires closed cooling system |
| MerCruiser | V8 (377 CID) Alpha | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | Requires closed cooling system |
| MerCruiser | V6 Bravo | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | For standard cooling systems |
| MerCruiser | V8 (305 CID) Bravo | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | For standard cooling systems |
| MerCruiser | V8 (350 CID) Bravo | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | For standard cooling systems |
| MerCruiser | V8 (377 CID) Bravo | Various | 4-Stroke | 2001–2016 | 57-865615-003/57-865615Q03 | For standard cooling systems |
Technical Specs
- Product Type
- Serpentine Belt
- Belt Length
- 2,704 mm
- Installation
- Direct OEM replacement
- Compatible Systems
- Engine accessory drive system
- Material
- OEM-specification rubber/polymer with reinforcement
- Application
- Sea water pump and accessory drive
- Other Technical Attributes
- Designed for marine environment exposure
What’s in the Box
- 1 x Serpentine Belt (57-865615Q03)
Installation Notes
- Disconnect the boat's battery terminals to prevent accidental starts.
- Locate the automatic tensioner pulley. Use a socket or wrench to rotate the tensioner and release pressure on the belt.
- Carefully remove the old serpentine belt from the pulleys, taking note of its routing path. A photo can be helpful.
- Inspect all pulleys for wobble, damage, or seizure. Clean any debris from the pulley grooves.
- Route the new belt according to the engine's diagram, ensuring it is properly seated on each pulley.
- Release the tensioner to apply pressure to the new belt. Double-check the belt's alignment.
- Reconnect the battery terminals, start the engine briefly, and confirm the belt operates smoothly.
Troubleshooting & FAQ
How do I know if this belt fits my specific engine?
Verify your engine is a MerCruiser V6 or V8 from 2001–2016 with a serial number between 0M320025 and 2A455872. Crucially, Alpha drives must have a closed cooling system, and Bravo drives must have a standard cooling system for this belt to fit.
What are common signs of a failing serpentine belt?
Telltale signs include loud squealing noises from the engine bay, visible cracks or fraying on the belt's surface, and intermittent or failed operation of accessories like the alternator, power steering, or water pump.
When should I replace my serpentine belt?
As a preventative maintenance measure, it is recommended to inspect the belt annually for wear and replace it every 3-5 years, depending on usage and conditions. Replace it immediately if you notice any damage.
Is this belt difficult to install?
For those with mechanical experience, installation is straightforward and involves releasing the belt tensioner. However, due to the importance of correct routing and tension, professional installation is recommended if you are unsure.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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