Sierra 18-3599-2 GM V6 & Small Block V8 Circulating Water Pump

The engine circulating pump for GM V6 and small block V8 marine engines. It moves coolant through the block and manifolds, and when the seal starts weeping or the bearing gets noisy it is on borrowed time. This one fits both standard and counter rotating engines and comes with the mounting gaskets.

• Fits GM V6 (s/n 1A063239 and below) and V8 305, 350 and 377 CID engines
• Fits both standard and counter rotating engines
• Mounting gaskets included
• Supersedes Sierra 18-3583
• Interchanges with MerCruiser, Crusader, Pleasurecraft and Volvo Penta numbers including MerCruiser 850399 and Volvo Penta 3853850

Replace the hoses and the thermostat while the front of the engine is apart. You already paid the labor to get in there. Use new gaskets and torque the bolts in a cross pattern. A pump housing pulled down unevenly will weep at the flange no matter how good the pump is.