Alternator Drive Belt – Fits Volvo Penta D1-30 & D2-40 Series (Replaces 21951188, 3812159)

Alternator Drive Belt – Fits Volvo Penta D1-30 & D2-40 Series

This high-quality alternator drive belt is designed to fit specific Volvo Penta marine diesel engines, including the D1-30 and D2-40 series. It serves as a reliable replacement for maintaining your engine's charging system and ensuring proper operation of belt-driven accessories.

Engineered from a durable synthetic rubber composite, this belt is built to OEM specifications for consistent fit and performance. It directly replaces original Volvo Penta parts, providing a dependable solution for routine maintenance or repair.

• Directly replaces Volvo Penta part numbers 21951188 and its superseded predecessor, 3812159.
• Engineered as a V-belt for installation on the engine alternator assembly.
• Constructed from a robust synthetic rubber composite to withstand the harsh marine environment.

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

This package includes:

• 1 x Alternator Drive Belt (replaces Volvo Penta 21951188 / 3812159)

Installation Guide

Follow these steps for a standard alternator belt replacement. Always consult your engine's service manual for model-specific instructions.

1. Safety First: Ensure the engine is off and cool. Disconnect the negative terminal from the battery to prevent accidental starting.
2. Locate the Alternator: Identify the alternator and the existing drive belt routing. It may be helpful to take a picture or draw a diagram.
3. Release Tension: Locate the alternator tensioner or adjusting bolt. Loosen it to release tension on the old belt.
4. Remove the Old Belt: Carefully slide the old belt off the alternator and crankshaft pulleys. Inspect the old belt for unusual wear patterns, which might indicate pulley misalignment.
5. Install the New Belt: Route the new belt around the pulleys according to your diagram or engine manual. Ensure the V-grooves are correctly seated in each pulley.
6. Apply Tension: Tighten the tensioning bolt until the belt is properly tensioned. A common rule of thumb is about a half-inch of deflection when pressed firmly at the longest span.
7. Tighten Bolts: Securely tighten all alternator mounting and adjusting bolts to the manufacturer's specified torque.
8. Final Check: Reconnect the battery terminal. Start the engine and listen for any unusual noises. Check that the belt is running smoothly and that the battery is charging.

Troubleshooting & FAQ

Q: How do I confirm this belt fits my Volvo Penta engine?

A: The most reliable method is to match the part number 21951188 or 3812159 from your old belt or service manual. This belt is confirmed to fit D1-30A, D1-30B, and D1-30F models. For D2-40 series engines, it is listed as compatible, but verifying your original part number is highly recommended due to model variations.

Q: What are the signs of a failing alternator belt?

A: Common symptoms include a persistent high-pitched squealing sound from the engine, a battery warning light on your dashboard, dimming lights, or visible damage to the belt itself, such as cracks, glazing, or fraying.

Q: How often should I replace my alternator drive belt?

A: We recommend regular visual inspections for any signs of wear. Belts should be replaced as part of your engine's scheduled maintenance intervals or immediately if damage is found. A proactive replacement can prevent power loss and potential damage to other engine components.

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.