Volvo Penta thermostat.
Your thermostat is an integral part of the cooling system and should be checked regularly for correct operation. Coolant should be changed, preferably with ready mixed, every 2 years and the heat exchanger removed for cleaning every 5 years.
Volvo Penta Part No: 877349
For Volvo Penta Diesel Engines: MD11C, MD11D, MD17C, MD17D freshwater engines.