V-Belt – Fits Volvo Penta TAMD/TMD 30, 31, 40, 41 Series Engines (Replaces 966978, 958359)
V-Belt – Fits Volvo Penta TAMD/TMD 30, 31, 40, 41 Series Engines (Replaces 966978, 958359) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
V-Belt – Fits Volvo Penta TAMD/TMD 30, 31, 40, 41 Series Engines (R...
Product Details
This high-strength V-Belt – Fits Volvo Penta TAMD/TMD 30, 31, 40, 41 Series Engines is designed for the alternator and raw water pump drive systems on a wide range of Volvo Penta 4-stroke diesel inboard and sterndrive engines. It covers models from the TAMD30A through the TMD41A series, as well as select KAD/TD, OMC, and MerCruiser engines.
This belt provides a direct interchange for Volvo Penta 966978 and 958359, Sierra 18-15435, OMC 912509, and Mercury 57-64416.
- Engineered with high-strength synthetic cords to resist stretching and withstand shock loads.
- Connects and drives essential engine-mounted components like the alternator and raw water pump.
- Precision-ground for a smooth, quiet, and reliable fit.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Volvo Penta | 966978, 958359 |
| Sierra | 18-15435 |
| OMC | 912509 |
| Mercury | 57-64416 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Volvo Penta engines: This belt fits a broad range of 30, 31, 40, 41, and select 42, 60, and 70 series models. Please verify your specific model number.
For OMC engines: Fits select Sterndrive 2.3L and 232 series models.
For MerCruiser engines: Used on certain rigging engines and 2.5L models.
| Brand | Model | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Volvo Penta | AD30A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AQAD30A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | MD30A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TAMD30A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TMD30A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AD31A/B/D-A/L-A/P-A/XD | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AQAD31A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | MD31A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TAMD31A/B/D/L-A/M-A/P-A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TMD31A/B/D/L-A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AD40B | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AQAD40A/B | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AQD40A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | MD40A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TAMD40A/B | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TMD40A/B/C | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AD41A/B/D/L-A/P-A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AQAD41A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | D41A/B/D/L-A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TAMD41A/B/D/H-A/L-A/M-A/P-A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TMD41A/B/D/L-A | 4-Stroke | 966978, 958359 | |
| Volvo Penta | KAD42B, KAMD42B | 4-Stroke | 966978, 958359 | With Additional Alternator |
| Volvo Penta | TD60D-83, TD60DG-83, TD60DPP-83 | 4-Stroke | 966978, 958359 | |
| Volvo Penta | AQD70B/C/CL/D | 4-Stroke | 966978, 958359 | |
| Volvo Penta | MD70B/BK/C | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TAMD70B/C/D/E | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TD70G-83, TD70GG-83, TD70GPP-83 | 4-Stroke | 966978, 958359 | |
| Volvo Penta | THAMD70C | 4-Stroke | 966978, 958359 | |
| Volvo Penta | TMD70B/C | 4-Stroke | 966978, 958359 | |
| OMC | Sterndrive 888 2.3L | 4-Stroke | 912509 | |
| OMC | 232 series (232AMFTC, 232APFTC) | 4-Stroke | 912509 | |
| MerCruiser | Rigging Engines | 4-Stroke | 57-64416 | |
| MerCruiser | 2.5L models | 4-Stroke | 57-64416 |
Technical Specs
- Product Type
- V-Belt
- Installation
- Engine driven components
- Fuel Type
- Diesel
- Connection
- Drive belt
- Dimensions
- Length: 43-1/2" (1105mm), Width: 29/64" (11.5mm)
- Other Technical Attributes
- High-strength synthetic cords for shock load resistance
What’s in the Box
- 1 x V-Belt (966978/958359)
Installation Notes
- Safety First: Before starting, disconnect the engine's battery and ensure the engine is cool to the touch.
- Access the Belt: Remove any guards or covers that block access to the belt and pulleys.
- Release Tension: Locate the alternator or tensioner pulley. Loosen the mounting bolts or adjustment mechanism to release tension on the old belt.
- Remove Old Belt: Carefully slide the old belt off the pulleys. Note its routing path. Taking a photo can be helpful.
- Inspect Pulleys: Before installing the new belt, spin each pulley by hand. They should turn smoothly without noise or wobble. Clean any debris from the pulley grooves.
- Install New Belt: Route the new V-belt according to the manufacturer's diagram or the path you noted earlier.
- Apply Tension: Carefully tighten the alternator or tensioner to apply the correct tension to the new belt. A common rule of thumb is about a half-inch of deflection when pressed firmly at the longest span.
- Final Check: Tighten all mounting bolts to the manufacturer's specified torque. Re-check the belt tension.
- Reconnect and Test: Reinstall any covers, reconnect the battery, and start the engine to ensure the belt runs smoothly and quietly.
Troubleshooting & FAQ
How do I find the right belt for my engine?
The best way to ensure a match is to cross-reference the part number printed on your old belt. If it matches any of the numbers in our Part Number Matrix (like Volvo Penta 966978 or Sierra 18-15435), it will fit. You can also use the compatibility table to find your engine model, but always visually compare your old belt to our product images and specifications.
What are the signs of a worn or failing V-belt?
Common signs include visible cracks, glazing (shiny surface), fraying, or missing chunks. You might also hear a high-pitched squealing sound from the engine, especially on startup or when under load. Dimming lights or a battery warning light can also indicate an alternator belt is slipping.
The notes for KAD42B mention an "Additional Alternator". Does this belt still fit?
Yes, this belt is specified for Volvo Penta KAD42B and KAMD42B models that are equipped with an additional alternator. Always verify the routing and length required by your specific engine configuration.
How often should this V-belt be replaced?
There is no fixed interval, as life depends on engine hours, operating conditions, and tension. We recommend inspecting the belt during every routine service and replacing it at the first sign of wear, or every 3-5 years as a preventative measure.
What happens if the belt is too loose or too tight?
A loose belt will slip, causing noise and preventing the alternator and water pump from functioning correctly, leading to undercharged batteries and potential overheating. A belt that is too tight puts excessive strain on the bearings of the components it drives (alternator, pumps), leading to premature failure of those parts.
Is this a single belt or a set?
This product includes one single V-belt as shown in the images and described in "What's in the Box."
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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