Sierra 18-70939 Exhaust Manifold Molded Hose
- Brand:
- Sierra
- Part no:
- 18-70939
Where to buy
View on Amazonpaid link
This is a Sierra replacement molded hose for the exhaust manifold on the starboard side. It connects the thermostat housing to that manifold on MCM and MIE engines built on the GM V-6 and V-8 blocks in 305 and 350 cid sizes. Sierra sells it as 18-70939 and describes it as a MerCruiser exhaust manifold molded hose, so that is the number to check against your old hose.
Our take
Where it fits is narrow: the hose joins the thermostat housing to the starboard exhaust manifold on 305 and 350 cid GM V-6 and V-8 MCM/MIE engines. Confirm your side and your engine size match that before you take the old hose off.