Serpentine Belt Tensioner – Fits Volvo Penta 4.3L, 5.0L, 5.7L & 8.1L (Replaces 3860079)

Serpentine Belt Tensioner – Fits Volvo Penta 4.3L, 5.0L, 5.7L & 8.1L (Replaces 3860079)

This serpentine belt tensioner pulley is designed for a wide range of Volvo Penta marine sterndrive engines, specifically models 4.3L, 5.0L, 5.7L, 7.4L, 8.1L, and 8.2L equipped with serpentine belt systems from approximately 1996 to 2015.

It serves as a direct replacement for Volvo Penta part numbers 3860079 and 3861009, ensuring a precise fit and restoring original performance.

• Installation Method: Direct replacement
• Fuel Compatibility: Gasoline
• Design: Features a sealed bearing design for enhanced durability in marine environments.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Belt Tensioner Pulley (Replaces 3860079/3861009)

Explosion Diagram

Installation Guide

Follow these general steps to replace the serpentine belt tensioner pulley. Always refer to your engine's service manual for detailed instructions and torque specifications.

1. Safety First: Disconnect the boat's battery before beginning any work.
2. Locate Tensioner: Identify the serpentine belt tensioner on the front of the engine.
3. Release Tension: Use a suitable breaker bar or tensioner tool to carefully pivot the tensioner arm and release the tension on the serpentine belt.
4. Remove Belt: Once slack, slide the serpentine belt off the tensioner pulley.
5. Remove Old Pulley: Unbolt the old tensioner pulley from the tensioner arm. Note the orientation of any washers or spacers.
6. Install New Pulley: Mount the new tensioner pulley, ensuring it is correctly aligned. Torque the retaining bolt to the manufacturer-specified value.
7. Reinstall Belt: Route the serpentine belt around all engine pulleys according to your engine's diagram.
8. Apply Tension: Pivot the tensioner arm again to allow the belt to slide completely onto the new pulley, then gently release the arm to apply tension. Ensure the belt is properly seated in all pulley grooves.
9. Final Check: Reconnect the battery. Start the engine and listen for abnormal noises while visually inspecting the belt and pulley for proper operation.

Troubleshooting & FAQ

How do I confirm this tensioner fits my Volvo Penta engine?
This tensioner is designed for Volvo Penta 4.3L, 5.0L, 5.7L, 7.4L, 8.1L, and 8.2L sterndrive engines with serpentine belt systems (approx. 1996–2015). The best way to guarantee fitment is to match your current part number to our direct replacements: 3860079 or 3861009. Also, visually compare your part to our product images.

What are the signs of a failing belt tensioner pulley?
Common symptoms include a persistent squealing, chirping, or grinding noise from the engine bay, especially at idle or during startup. You may also notice accelerated or uneven wear on the serpentine belt itself. Failure of the pulley can lead to the belt coming off, causing a loss of power to accessories like the alternator and water pump.

Is this a complete tensioner assembly or just the pulley?
This product listing is for the serpentine belt tensioner pulley only. It is designed to be a direct-fit replacement for the original pulley on your existing tensioner assembly.

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.