Sierra 18-70939 Mercruiser Exhaust Manifold Molded Hose - Thermostat Housing to Starboard

The Sierra 18-70939 is a high-quality replacement exhaust manifold molded hose designed to connect the thermostat housing to the starboard exhaust manifold on MerCruiser stern drive engines. Built to withstand the demanding conditions of the marine environment, this preformed hose ensures a precise, leak-free fit for reliable engine cooling system performance.

Key Features:

• Direct replacement for the thermostat housing to starboard exhaust manifold connection
• Precisely molded shape for a drop-in fit — no cutting or trimming required
• Engineered to meet or exceed OEM specifications
• Constructed from durable materials rated for the high-heat marine exhaust environment
• Designed for MCM/MIE GM V-6 and V-8 engines (305 and 350 CID)

Sierra marine parts are manufactured to meet or exceed the original equipment specifications they replace. As a trusted supplier to OEM engine manufacturers and boat builders, Sierra delivers the quality and fitment you expect for your MerCruiser stern drive cooling system.