Sierra Marine V-Belt 18-15480 | 48 in. / 121.9 cm × 29/64 in. / 11.5 mm
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Sierra Marine V-Belt 18-15480
- Part Number: 18-15480 (Sierra)
- Brand: Sierra
- Product Type: Cogged Marine V-Belt
- Effective Length: 48 in. / 121.9 cm
- Top Width: 29/64 in. / 11.5 mm
- UPC: 030999566614
The Sierra 18-15480 is a cogged marine V-belt for selected MerCruiser inboard and sterndrive accessory-drive systems. High-strength synthetic cords resist stretching and shock-load failure. The precision-moulded cog profile improves flexibility and allows greater airflow to reduce heat buildup. Rubber sidewalls maintain positive, non-slip pulley contact.
Compatible Applications
Verified MerCruiser V8 applications:
- MerCruiser 440 TRS — 1983–1986
- MerCruiser 450 — 1995–1996
- MerCruiser 460 TRS — 1983–1986
- MerCruiser 465 / 502 CID / 8.2L — selected 1990–1992
- MerCruiser 502 MAG Bravo / 8.2L — selected 1990–1997
- MerCruiser 502 MAG EFI / 8.2L — selected 1994–1995
- MerCruiser 502 MAG MPI / 8.2L — selected 1996–1997
Broader replacement listings also associate this belt with selected 5.0L, 5.7L, 7.4L, and 8.2L MerCruiser V8 accessory-drive configurations. Always confirm engine model, serial number, existing OEM belt number, and pulley arrangement before ordering. Nearby Sierra belts can differ by as little as 1 in. / 25.4 mm — matching the OEM part number and belt width is more reliable than selecting by displacement alone.
Cross-Reference Part Numbers
- Sierra: 18-15480
- Supplier/Catalogue Reference: 47-15480
- Mercury / MerCruiser: 57-48122
- Mercury Quicksilver: 57-48122Q
- Mallory: 9-55003
- OMC: 0509295
- GLM: 89440
When to Replace This Belt
- Cracks visible between the cogs
- Frayed or worn edges
- Glazed, hardened, or oil-contaminated surface
- Increased belt dust around pulleys
- Slipping, squealing, or loss of tension
- Belt has stretched beyond adjustment range
Installation Notes
- Inspect pulley grooves for wear, corrosion, and alignment before installing
- Confirm correct belt routing for your engine configuration
- Do not force the belt over pulley flanges with sharp tools — this can damage internal cords
- Set belt tension to the engine manufacturer's specification
- Rotate the assembly by hand to confirm full pulley seating
- Recheck tension after initial operation
Parts Desk Insights
Best use case: This belt is the right choice for pre-season service and routine maintenance on MerCruiser 502 CID / 8.2L V8 inboard and sterndrive boats running a conventional V-belt accessory drive. If your engine specifies OEM references 57-48122 or 57-48122Q, this is the direct replacement to have on hand before launch. It also serves as a practical onboard spare — a belt failure on these big-block engines can simultaneously disable raw water cooling and battery charging.
Common issue: A 48-inch belt is not automatically the correct fit. Customers frequently order by engine displacement without verifying the pulley arrangement or OEM number, which leads to slipping, overheating, or premature accessory-drive wear. Always match the original OEM belt number and verify the belt width and pulley configuration. If your engine has been converted to a serpentine-belt system, this belt does not apply.
For a complete cooling system service, pair this belt with a raw water pump impeller. See the PCM Impeller Kit RP061017 and PCM / Crusader RP061022 Raw Water Pump Impeller for compatible options.
Need a different belt size? Browse other sizes in the Sierra V-Belt series: Sierra V-Belt 47-15400, Sierra V-Belt 47-15410, Sierra V-Belt 47-15440, Sierra V-Belt 47-15450, Sierra V-Belt 47-15455, Sierra V-Belt 47-15460, Sierra Marine V-Belt 18-15470, and Sierra V-Belt 47-15550.
Shop all Engine Parts & Maintenance or browse Propulsion & Powertrain for related components.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
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Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
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