Volvo Penta Thermostat.
Your thermostat is an important 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: 875796
For Volvo Penta Diesel Engines: MD2, MD7A, MD7B, MD6A, MD6B