Idler Pulley – Fits Volvo Penta D4 & D6 Series Diesel Engines (3847482)

Idler Pulley – Fits Volvo Penta D4 & D6 Series Diesel Engines (3847482)

This aftermarket idler pulley is engineered for Volvo Penta D4 series (180–300 HP) and D6 series (280–435 HP) 4-stroke diesel engines, covering models from 2003 to the present. It maintains proper serpentine belt tension, which is critical for the reliable operation of engine accessories.

Designed as a direct replacement for Volvo Penta part number 3847482, this pulley ensures a precise fit and straightforward installation without the need for modifications.

• Compatibility: Designed specifically for Volvo Penta D4 & D6 diesel engines.
• Installation: Features a direct bolt-on design for easy replacement.
• Built for Durability: Constructed from high-grade durable materials to withstand marine engine conditions.

Part Number Cross-Reference

Use this table to confirm that this part is a suitable replacement for your original component.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Idler Pulley (3847482)

Explosion Diagram

Installation Guide

Follow these general steps for replacement. Refer to your engine’s service manual for detailed instructions and torque specifications.

1. Safety First: Disconnect the battery terminals to prevent accidental starting.
2. Locate Components: Identify the serpentine belt, the belt tensioner, and the old idler pulley.
3. Release Belt Tension: Use a breaker bar or appropriate tool on the belt tensioner to loosen the serpentine belt.
4. Remove Belt: Carefully slide the belt off the idler pulley and other accessory pulleys.
5. Remove Old Pulley: Use a socket wrench to unbolt and remove the old idler pulley from its mounting point.
6. Clean Surface: Thoroughly clean the mounting surface to ensure the new pulley sits flush.
7. Install New Pulley: Position the new idler pulley and hand-tighten the mounting bolt.
8. Torque to Spec: Use a torque wrench to tighten the bolt to the manufacturer's recommended specification. Do not overtighten.
9. Reinstall Belt: Route the serpentine belt according to the diagram in your service manual, ensuring it is seated correctly in all pulley grooves.
10. Final Check: Reconnect the battery, start the engine, and listen for any unusual noises. Visually inspect the pulley and belt to confirm smooth operation.

Troubleshooting & FAQ

Q: How can I confirm this idler pulley fits my engine?
A: This pulley is designed for specific Volvo Penta D4 and D6 series diesel engines. To ensure a correct fit, please find your exact engine model (e.g., D4-225I-D) in the "Compatible Engine Models" table above. Verifying that your original part number is 3847482 is the most reliable method.

Q: What are common signs that my idler pulley needs replacement?
A: Key symptoms of a failing idler pulley include a persistent squealing, chirping, or grinding noise from the engine bay, visible wobble or excessive play in the pulley itself, or a serpentine belt that repeatedly slips off or shows premature wear.

Q: Is this part built to the same standards as the original Volvo Penta component?
A: This is an aftermarket component manufactured from high-grade durable materials designed to meet or exceed OEM performance requirements. While the material composition may differ, it is built for reliable performance in demanding marine environments.

Q: OEM vs. Aftermarket?
A: 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.

Q: How fast do you ship and how much does it cost?
A: 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.

Q: What is your warranty and return policy?
A: 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.