21148860 Thermostat Housing | Genuine Volvo Penta Part

🔧 Product Description

A genuine Volvo Penta cast thermostat housing used with the circulation pump and thermostat on selected 3.0-litre GXi marine petrol engines. The housing supports thermostat 21148403 and directs coolant between the engine, pump and cooling circuit.

🚤 Compatibility

Typically suits:

• Volvo Penta 3.0GXiC-J
• Volvo Penta 3.0GXi-J

• HP Range: Approximately 150 HP

⚙️ Key Features

• Genuine Volvo Penta 3.0L thermostat housing
• Used with thermostat 21148403 and the matching circulation pump
• Machined sealing faces and coolant passages
• Maintains correct thermostat location and coolant distribution
• Inspect the casting, threads and mating surfaces before installation
• Engine type: 3.0-litre inline-four marine petrol engine

🔌 Function

Houses the thermostat and distributes coolant between the circulation pump, engine passages and external cooling circuit.

⚠️ Common Signs of Failure

• Coolant leakage from a cracked casting or corroded sealing face
• Damaged hose necks, threads or mounting bosses
• Repeated thermostat-seal failure
• Restricted passages or internal corrosion
• Engine overheating or unstable temperature caused by poor coolant distribution

🛠️ Service Notes

• Clean both faces back to bare metal without gouging them, and check the housing and its mating face for corrosion, pitting and distortion before fitting
• Fit a new gasket or seal, and fit the thermostat and its sealing ring the right way round with any vent or jiggle pin positioned as it was originally
• Tighten the bolts evenly in stages to the figures in the workshop manual for your engine; these castings are light and pull out of flat easily
• Check the hoses, clips and any sensor or plug that screws into the housing while it is off, and use sealant only where it is specified
• Fill and vent the system, run the engine to temperature, and confirm the thermostat opens and the joints stay dry

🔄 Supersession & Cross Reference

OEM / Related Numbers

• 21148403 - associated 143°F / 62°C thermostat
• 3858340 - associated circulation-pump reference
• 3863441 - associated hose-clamp reference

📦 Condition

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