Sierra 18-3309 Water Pump Kit for Mercruiser Bravo Gen II Lower, s/n D469859 and Up

The Sierra 18-3309 Water Pump Kit is a complete lower water pump rebuild kit for Mercruiser Bravo Gen II lower units with serial numbers D469859 and up. This kit supplies the core wear components needed to restore proper cooling water flow to the drive without requiring purchase of a full pump assembly, making it the standard choice for scheduled water pump maintenance or a no-cooling-flow repair. The kit includes a water tube, impeller, and the water pump base to gear housing gasket, giving you the parts that wear or fail most often in this pump design. Because the impeller is the component most responsible for pump output, replacing it along with the water tube and gasket in a single kit helps ensure a complete, leak-free rebuild in one service interval rather than discovering a worn secondary part after the housing is already open. This kit does not include the upper housing; if you need the same kit with the upper housing included, that is a separate part number. Each component is manufactured to meet or exceed the original equipment part it replaces, and the kit is backed by Sierra's warranty coverage on all Sierra parts.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3309
• Product Type: Water Pump Kit
• Application: Bravo, Gen II Lower
• Serial Number Range: D469859 and Up
• Weight: 1.2 pounds
• Kit Contents: Water Tube (18-3109, O.E. 23-29804), Impeller (18-3017, O.E. 47-89984), Water Pump Base to Gear Housing Gasket (18-2919)
• Related Kit: Same kit without upper housing available as 18-3214

Fitment

• Mercruiser Bravo, Gen II Lower, serial number D469859 and up

Replaces (OEM)

• GLM 12085

Frequently Asked Questions

What does the Sierra 18-3309 Water Pump Kit include? The 18-3309 kit includes a water tube (18-3109), an impeller (18-3017), and a water pump base to gear housing gasket (18-2919), covering the main wear parts in a Bravo Gen II lower unit water pump rebuild.

What drive does the 18-3309 water pump kit fit? This kit is designed for Mercruiser Bravo Gen II lower units, specifically units with serial number D469859 and up.

Does the 18-3309 kit include the upper housing? No, the 18-3309 kit does not include the upper housing. The same kit with the upper housing included is sold under a different Sierra part number, 18-3214.

Is the Sierra 18-3309 kit compatible with GLM 12085? Yes, the 18-3309 Water Pump Kit is designed to be interchangeable with GLM 12085.

How much does the 18-3309 Water Pump Kit weigh? The Sierra 18-3309 Water Pump Kit weighs 1.2 pounds.

What is the OEM number for the impeller in the 18-3309 kit? The impeller included in the 18-3309 kit is Sierra part 18-3017, cross-referenced to O.E. Number 47-89984.

What is the OEM number for the water tube in the 18-3309 kit? The water tube in the 18-3309 kit is Sierra part 18-3109, cross-referenced to O.E. Number 23-29804.

Is the 18-3309 kit genuine Sierra or aftermarket? The 18-3309 is a genuine Sierra part, manufactured to meet or exceed the specifications of the original equipment component it replaces.

Is a gasket included with the 18-3309 kit? Yes, the kit includes a water pump base to gear housing gasket, Sierra part 18-2919.

Is the 18-3309 covered by warranty? The Sierra 18-3309 Water Pump Kit qualifies for and is covered under Sierra's standard parts warranty.

What serial number range does the 18-3309 kit apply to? The 18-3309 is specified for Mercruiser Bravo Gen II lower units with serial number D469859 and up.

What is the difference between 18-3309 and 18-3214? Both are the same water pump kit for the Bravo Gen II lower unit, but 18-3309 does not include the upper housing while 18-3214 is the equivalent kit without the upper housing packaged separately; confirm which configuration your rebuild requires before ordering.