21412646 Thermostat | Genuine Volvo Penta Part

🔧 Product Description

Engine-coolant thermostat with an 86°C opening temperature for Volvo Penta D9A2 marine and industrial applications using the corresponding thermostat housing. It regulates coolant flow through the heat exchanger or radiator to stabilise engine temperature.

🚤 Compatibility

Typically suits:

• Volvo Penta D9A2L MH
• Volvo Penta D9A2M MP
• Volvo Penta TAD1360-62VE
• Volvo Penta TAD1363-65VE
• Volvo Penta TAD1371-75VE
• Volvo Penta TAD1351-53VE

• Engine Family: D, TAD

⚙️ Key Features

• Genuine Volvo Penta 86°C thermostat
• Specified for D9A2 cooling systems
• Controls warm-up and operating coolant flow
• Supersedes earlier thermostat references in the same family
• Engine type: Volvo Penta D9 inline six-cylinder diesel

🔌 Function

Closes during warm-up and opens near 86°C to direct coolant through the heat-rejection circuit and maintain stable engine temperature.

⚠️ Common Signs of Failure

• Engine runs too cool or warms up slowly
• Overheating under load
• Temperature fluctuates as the thermostat sticks
• Coolant bypasses because the valve is jammed open
• Corrosion, scale or distorted wax-element housing

🛠️ Service Notes

• Let the engine cool fully and drain coolant to below the housing before opening it, catching what comes out
• Clean both faces of the housing without scoring them, and fit a new gasket or sealing ring with the thermostat — the old seal should never be reused
• Fit the thermostat the right way round, with the sensing element towards the engine and any vent or bleed hole positioned as the original was, and check it is properly seated before the cover goes on
• Pull the housing fasteners down evenly and to the figure in the workshop manual for your engine; an unevenly tightened cover distorts and weeps
• Refill with the specified coolant, vent the system, then run up to temperature and check both for leaks and that the engine reaches and holds its normal running temperature

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21412646 → Supersedes 21264664 → Supersedes 3848130

OEM / Related Numbers

• 21264664 earlier number superseded by this part
• 3848130 earlier number superseded by this part

Aftermarket / Verified Equivalents

• RECMAR: RM21412646
• SLP: T-646
• Calorstat by Vernet: THS18201.82
• DT Spare Parts: 2.15077
• NRF: 725013
• PE Automotive: 259.020-00A
• Trucktec Automotive: 03.19.100

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging