Water Pump Impeller Kit – Fits Volvo Penta 3.0-8.1L V6/V8 (Replaces 21213660, 21951348)

$19.99

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

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Water Pump Impeller Kit is an essential replacement part for maintaining your engine's cooling system. It is designed for a direct fit on a wide range of Volvo Penta 3.0L, 4.3L, 5.0L, 5.7L, and 8.1L V6/V8 gas engines manufactured from 2005 to the present.

It serves as a direct interchange for several OEM and aftermarket parts, including Volvo Penta 21213660 and 21951348, Sierra 18-3277 and 18-3081, Johnson 09-812B-1, and Indmar S685007.

Made from durable neoprene rubber with a brass insert for longevity in marine environments.
Installation requires a glycerin-based lubricant or dish soap for proper seating and to prevent damage.
Annual replacement is recommended to ensure optimal engine performance and prevent overheating.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket brands.

Brand	Part Number	Notes
Volvo Penta	21213660	Superseded by 21951348
Volvo Penta	21951348	Current OEM Number
Sierra	18-3277	Aftermarket Interchange
Sierra	18-3081	Aftermarket Interchange
Johnson	09-812B-1	Pump impeller reference
Indmar	S685007	Engine manufacturer equivalent
QuickMarine	21213660	Aftermarket cross-reference

Engine & Model Compatibility

Confirm your engine model and year in the tables below. Note that for Volvo Penta applications, this impeller kit only fits pumps that use LONG screws for the housing cover, typically found on 2005 and newer boats.

Brand	Model Series	Rated HP	Years	OEM Part No.	Notes
Volvo Penta	3.0L	Various	2005–Present	21213660/21951348	Fits carbureted and fuel-injected gas engines
Volvo Penta	4.3L, 5.0L, 5.7L	Various	2005–Present	21213660/21951348	Fits V6/V8 carbureted and fuel-injected gas engines
Volvo Penta	8.1L	Various	2005–Present	21213660/21951348	Fits V8 gas engines

Brand	Model	Years	OEM Part No.	Notes
Indmar	Monsoon	1996–Present	S685007	Fits all Monsoon models (320HP–350HP)
Johnson	F6B-9	N/A	09-812B-1	Fits this raw water pump model

Technical Specs

Product Type: Sea Water Pump Impeller Kit
Installation: Direct Fit Replacement
Impeller Material: Durable Neoprene Rubber with Brass Insert
Blade Count: 12
Spline Count: 12
Impeller Dimensions: Width: 49.2mm (1-15/16") × Diameter: 57.1mm (2-1/4")
Shaft Size: 16mm (5/8")
Recommended Replacement: Annually or every 100 hours of use

What’s in the Box

1 x Neoprene Impeller (12-Blade)
1 x Paper Gasket
1 x O-ring Seal

Installation Notes

Before starting, disconnect the boat's battery and close the water inlet seacock.
Locate the sea water pump housing and carefully remove the cover screws and cover plate.
Note the orientation of the old impeller's blades before removing it. Use needle-nose pliers to grip the hub and pull it out.
Clean the inside of the pump housing thoroughly and inspect for any scoring or damage.
Generously lubricate the new impeller and the inside of the housing with a glycerin-based lubricant or simple dish soap.
Install the new impeller with a slight twisting motion, ensuring the blades bend in the same direction as the old one (in the direction of engine rotation).
Place the new gasket or O-ring onto the clean housing surface.
Reinstall the cover plate and tighten the screws evenly in a star pattern to ensure a proper seal.
Once complete, open the seacock, reconnect the battery, start the engine, and immediately check for any water leaks around the pump housing.

Troubleshooting & FAQ

How do I confirm this impeller fits my Volvo Penta engine?

This impeller fits most Volvo Penta V6 and V8 gas engines from 2005 to present. The most critical check is to confirm your sea water pump uses LONG screws for the housing cover. If your pump uses short screws, this part is not compatible. Always verify against the part numbers and dimensions provided.

What are common signs that my impeller needs replacing?

The most common symptoms of a worn or failed impeller are engine overheating, a higher-than-normal temperature reading on your gauge, or reduced water flow from the exhaust outlet. It is recommended to perform a visual inspection at least once a year.

How often should this impeller be replaced?

For best results and to prevent unexpected failure, we recommend replacing your sea water pump impeller annually or every 100 hours of engine use, whichever comes first. This is a critical preventative maintenance item.

What lubricant should I use during installation?

Use a water-based lubricant like glycerin or simple dish soap on the inside of the pump housing and on the impeller itself. Do not use any petroleum-based greases or oils, as they can cause the neoprene rubber to swell and degrade over time.

What is the difference between an OEM and an aftermarket part?

This listing is for a high-quality aftermarket replacement part, not an OEM (Original Equipment Manufacturer) component. It has been engineered to meet or exceed OEM-level specifications using comparable materials. Our parts are manufactured in an ISO 9002 certified facility and are batch-inspected to ensure quality and consistency.

What are your shipping speed and cost?

We ship worldwide quickly, with a typical transit time of 5–15 days for most destinations. Standard shipping is free on all orders. Expedited shipping options, if available for your location, will be presented at checkout.

What is the warranty and return policy?

This product is covered by a 1-year warranty against manufacturing defects under normal use conditions. If you encounter an issue, please contact our support team with your order details for assistance. Returns are accepted within our standard window, provided the item is unused and in its original packaging. Please see our full policy page or contact us for instructions.

Safety & Important Info

Verify the product images and specifications against your original part before purchasing. If any detail differs—even if your model is listed as compatible—do not order.
This is an aftermarket replacement part, not an original OEM component. All mentions of brand names and part numbers are for reference purposes only.
Professional installation is highly recommended for safety, proper function, and to prevent damage to your engine's cooling system.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to meet strict OEM-level tolerances and thoroughly tested for demanding real-world conditions.
Fast Global Fulfillment — Enjoy free standard delivery to most regions worldwide, with typical transit times of just 5–15 days.
Manufacturer-Direct Value — By working directly with our manufacturing partners, we offer fair, competitive pricing without ever 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.