Serpentine Drive Belt – Fits Volvo Penta D4 & D6 Series Engines 145-480HP (Replaces 21405494, 3583729, 21405444)

Serpentine Drive Belt – Fits Volvo Penta D4 & D6 Series Engines

This aftermarket serpentine drive belt is engineered for a precise fit on Volvo Penta D4 and D6 series marine diesel engines, covering models from 145 to 480 horsepower manufactured between 2003 and 2025. It serves as a direct, reliable replacement for the original component, ensuring your engine's accessories are powered efficiently.

This belt is a direct replacement for Volvo Penta OEM part numbers: 21405494, 3583729, and 21405444. It is designed to meet or exceed original equipment specifications for performance and durability.

• Design: Features a multi-rib (serpentine) design for optimal grip and flexibility.
• Material: Constructed from durable, reinforced rubber to withstand the harsh marine environment.
• Installation: Mounts directly to the engine's pulley system.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Serpentine Drive Belt (Replaces 21405494/3583729/21405444)

Installation Guide

1. Safety First: Ensure the engine is off and cool, and disconnect the battery.
2. Locate the Belt: Identify the serpentine belt and its routing path around the various pulleys. It's helpful to take a photo or find a diagram for your specific engine model.
3. Release Tension: Use a wrench or socket on the automatic tensioner pulley to release the belt's tension.
4. Remove Old Belt: Carefully slide the old belt off the pulleys.
5. Inspect Pulleys: Before installing the new belt, spin each pulley by hand to check for wobble, resistance, or noise, which could indicate a failing component.
6. Install New Belt: Following your diagram, route the new belt around the pulleys, leaving the tensioner pulley for last.
7. Apply Tension: Re-engage the tensioner to apply the correct tension to the new belt.
8. Final Check: Double-check that the belt is correctly seated in the grooves of every pulley. Reconnect the battery and start the engine to ensure smooth operation.

Troubleshooting & FAQ

How do I confirm this belt fits my Volvo Penta D4 or D6 engine?
First, check the comprehensive "Compatible Engine Models" table on this page to find your specific model and year. Second, verify that your existing belt's part number matches one of the OEM numbers listed: 21405494, 3583729, or 21405444. Matching both is the best way to ensure a correct fit.

What are the signs that my serpentine belt needs replacing?
Common indicators of a failing belt include loud squealing or chirping noises from the engine, visible cracks or fraying on the belt's surface, glazing or shininess on the ribbed side, or pieces of rubber missing. Any visible damage warrants an immediate replacement to avoid engine accessory failure.

How often should I inspect or replace my marine engine's serpentine belt?
It is recommended to inspect the belt during every routine engine service. There is no fixed replacement interval, as life depends on hours, load, and conditions. However, it should be replaced immediately if any signs of wear, such as cracking, fraying, or glazing, are present.

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?

• 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.