Sierra Marine Circulating Water Pump 18-3599-2 – MerCruiser / Volvo Penta GM V8 Engine Cooling Pump
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
The Sierra 18-3599-2 Circulating Water Pump is a complete, engine-mounted cooling pump designed for GM-based V8 marine engines used in MerCruiser and Volvo Penta applications. This pump circulates coolant (or raw water in open systems) through the engine block to maintain proper operating temperature and prevent overheating.
This is a belt-driven circulating pump, not a raw water impeller pump. It is a critical component in the engine’s cooling system and is responsible for maintaining consistent coolant flow at all RPM ranges.
Manufactured from new castings and built to meet or exceed OEM specifications, this pump ensures long-lasting durability and reliable performance in marine environments.
Key Features
- Complete circulating water pump assembly
- Belt-driven, engine-mounted design
- Provides continuous coolant circulation
- Marine-grade construction with corrosion resistance
- Direct OEM replacement fit and performance
- Built from new castings (not remanufactured)
- Sierra limited lifetime warranty
Engine Compatibility
MerCruiser (GM-Based V8 Engines)
- 5.0L (305 CID)
- 5.7L (350 CID)
- 6.2L (377 CID)
Volvo Penta
- 5.0L V8
- 5.7L V8
OMC / Inboard Applications
- GM-based V8 engines (select models)
➡️ Fits standard rotation small block GM marine engines
Serial Number Fitment Notice
Fitment depends on:
- Engine rotation (standard vs reverse)
- Pulley configuration
- Mounting style
⚠️ Always confirm using engine serial number before ordering to ensure correct rotation and fitment.
When This Part Needs Replacement
Replace the circulating pump if you notice:
- Engine overheating at all RPM ranges
- Coolant or water leaking from weep hole
- Bearing noise or pulley wobble
- Reduced coolant circulation
- Corrosion inside pump housing
Typical lifespan: 5–10 years depending on usage
Installation Notes
- Verify engine rotation before install
- Replace gasket and ensure clean mounting surface
- Inspect belts and pulleys during service
- Torque bolts evenly to OEM specs
- Prime cooling system before startup
Alternate / Superseded Part Numbers
OEM Cross References
- Mercury / MerCruiser:
- 807151A9
- 46-807151A9
- Volvo Penta:
- 3857796
Aftermarket Cross References
- Mallory: 9-42607
- GLM: 15090
Shipping
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.