Changes to Mercruiser Parts Thermostat Housings
Thermostat Housings No Longer Available
MCM, MIE V6 and V8: P/N 807123A 2 or 807790A 1 Cast Iron Thermostat Housings and P/N 806235A 1 Stainless Steel Thermostat Housing.
Replacement Parts
Three new replacement thermostat housing kits are available for these engines. Each type of housing is designed to give better thermostat response to the engine in relation to the type of seawater pump that the engine uses. Affected parts lists will be updated soon.
NOTE: These kits have shorter bolts included in them for use on engines that do not have a lifting eye.
NOTE: Because of water flow differences, do not put Alpha housings on Bravo engines or Bravo housings on Alpha engines.
860256A 3 Thermostat Housing. USE ONLY ON Alpha Sterndrive engines. (’ALPHA’ cast on top of housing. P/N 860256C or 860256C 3 on bottom).
860256A 4 Thermostat Housing. USE ONLY ON Bravo Sterndrive, ski or inboard V6 or V8 (350 cid) engines. (No name cast on top. P/N 860256C1 or 860256C4 on bottom).
861006A 1 Thermostat Housing. USE ONLY ON Bravo Sterndrive, ski or inboard V8 (454 or 502 cid) engines. (No name cast on top. P/N 861006C on bottom).

a -Thermostat Housing.