Serpentine Belt Idler Pulley – Fits Volvo Penta 3.0L, 4.3L, 5.0L, 5.7L, 8.1L Engines (Replaces 3861009)
Serpentine Belt Idler Pulley – Fits Volvo Penta 3.0L, 4.3L, 5.0L, 5.7L, 8.1L Engines (Replaces 3861009) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
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.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Serpentine Belt Idler Pulley – Fits Volvo Penta 3.0L, 4.3L, 5.0L, 5...
Product Details
This aftermarket Serpentine Belt Idler Pulley is designed for a wide range of Volvo Penta marine gas engines, including 3.0L, 4.3L, 5.0L, 5.7L, and 8.1L models. It fits various GL, GXi, OSi, and Gi series engines manufactured from approximately 2000 to 2010, ensuring reliable performance for your sterndrive system.
This component is a direct replacement for Volvo Penta part number 3861009.
- Engineered for direct-fit installation.
- Constructed from durable metal housing to withstand marine environments.
- Maintains proper serpentine belt tension and alignment.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Volvo Penta | 3861009 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits a broad range of Volvo Penta gas sterndrive engines. Please verify your specific model is listed.
| Brand | Model | Stroke | OEM Part No. |
|---|---|---|---|
| Volvo Penta | 3.0GLM-C | 4-Stroke | 3861009 |
| Volvo Penta | 3.0GLP-C, 3.0GLP-D, 3.0GLP-E, 3.0GLP-J, 3.0GLP-N | 4-Stroke | 3861009 |
| Volvo Penta | 3.0GXi-J, 3.0GXiC-J | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GL-A, 4.3GL-B, 4.3GL-C, 4.3GL-D | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GL-E, 4.3GL-EF, 4.3GL-G, 4.3GL-GF | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GL-J, A.3GL-JF, 4.3GL-P | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GXi-A, 4.3GXi-C, 4.3GXi-CF | 4-Stroke | 3861009 |
| Volvo Penta | 4.3OSi-C, 4.3OSi-CF | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GXi-D, 4.3GXi-DF | 4-Stroke | 3861009 |
| Volvo Penta | 4.3OSi-D, 4.3OSi-DF | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GXi-E, 4.3GXi-EF, 4.3OSi-E | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GXiE-M, 4.3GXiE-Q | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GXiE-225-R, V6-225-E-A, 4.3GXiE-225-S | 4-Stroke | 3861009 |
| Volvo Penta | 4.3GXi-F | 4-Stroke | 3861009 |
| Volvo Penta | 5.0GL-A, 5.0GL-B, 5.0GL-C, 5.0GL-D | 4-Stroke | 3861009 |
| Volvo Penta | 5.0GL-E, 5.0GL-F, 5.0GL-FF, 5.0GL-H, 5.0GL-HF | 4-Stroke | 3861009 |
| Volvo Penta | 5.0GL-J, 5.0GL-JF | 4-Stroke | 3861009 |
| Volvo Penta | 5.0GXi-B, 5.0GXi-BF | 4-Stroke | 3861009 |
| Volvo Penta | 5.0GXi-E, 5.0GXi-EF, 5.0GXi-F, 5.0GXi-FF | 4-Stroke | 3861009 |
| Volvo Penta | 5.0GXi-G, 5.0GXi-GF, 5.0GXi-J, 5.0GXi-JF, 5.0GXi-N | 4-Stroke | 3861009 |
| Volvo Penta | 5.0OSi-A, 5.0OSi-B, 5.0OSi-BF, 5.0OSi-E, 5.0OSi-EF | 4-Stroke | 3861009 |
| Volvo Penta | 5.0OSi-F, 5.0OSi-FF, 5.0OSi-G, 5.0OSi-GF, 5.0OSi-J, 5.0OSi-JF | 4-Stroke | 3861009 |
| Volvo Penta | 5.7Gi-300-J, 5.7Gi-300-JF, 5.7OSi-300-J, 5.7OSi-300-JF | 4-Stroke | 3861009 |
| Volvo Penta | 5.7GXi-J, 5.7GXi-JF, 5.7OSXi-J, 5.7OSXi-JF, 5.7GXi-N, 5.7Gi-300-N | 4-Stroke | 3861009 |
| Volvo Penta | 8.1Gi-J, 8.1Gi-JF, 8.1OSi-J, 8.1OSi-JF | 4-Stroke | 3861009 |
| Volvo Penta | 8.1GXi-J, 8.1GXi-JF, 8.1GSi-A | 4-Stroke | 3861009 |
Technical Specs
- Product Type
- Serpentine Belt Idler Pulley
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Housing Material
- Metal
- Dimensions
- 3.5 inches diameter (88.9 mm)
- Warranty
- 1 year (from aftermarket suppliers)
What’s in the Box
- 1 x Serpentine Belt Idler Pulley (3861009)
Installation Notes
- Disconnect the boat's battery for safety.
- Locate the serpentine belt tensioner and release the tension on the belt.
- Remove the serpentine belt from the idler pulley.
- Unbolt and remove the old idler pulley. Note the orientation and any washers or spacers.
- Install the new idler pulley, ensuring it is correctly aligned.
- Torque the mounting bolt to the manufacturer’s specified value.
- Reroute the serpentine belt according to the engine's diagram.
- Apply tension back to the belt using the tensioner.
- Reconnect the battery and start the engine to check for proper operation and alignment.
Troubleshooting & FAQ
How do I know if my idler pulley is failing?
Common signs of a failing idler pulley include a squealing or grinding noise from the engine bay, visible wobble or play in the pulley, and uneven wear or damage to the serpentine belt.
Can I replace just the pulley, or do I need the entire tensioner assembly?
This part is the idler pulley itself. In many cases, the idler pulley can be replaced independently of the belt tensioner assembly. However, inspect the tensioner for wear or weakness, as it may be wise to replace both if the tensioner is also old or failing.
How often should I inspect the serpentine belt and pulleys?
It is good practice to visually inspect the serpentine belt and all pulleys during routine engine maintenance, such as oil changes. Listen for abnormal noises and check for belt wear. A comprehensive inspection should be performed at least annually.
What's the difference between an idler pulley and a tensioner pulley?
An idler pulley is a non-adjustable pulley that helps guide the serpentine belt. A tensioner pulley is attached to a spring-loaded or adjustable arm that applies pressure to the belt to maintain proper tension. This listing is for a stationary idler pulley.
Is any special tool required for installation?
Standard metric or imperial sockets and a wrench set are usually sufficient. A belt tensioner tool or a long-handled breaker bar may be needed to release the belt tension safely and effectively.
What is the difference between OEM and aftermarket parts?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.
How fast do you ship and what is the cost?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free to most locations; expedited options may be available at checkout.
What is your warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window for items that are unused and in their original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is highly recommended for safety and optimal 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 quality control.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
