Thermostat Kit 140°F / 60°C – Fits Volvo Penta Marine (Replaces 875796, 18-3665)

$37.49

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Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Thermostat Kit 140°F / 60°C is engineered for a wide range of Volvo Penta marine engines, including gasoline models from 1978–1994 (like the AQ120B and AQ140A) and diesel models from 1975–1993 (such as the MD6 and MD7 series). It ensures your engine maintains the correct operating temperature for optimal performance and fuel efficiency.

This kit serves as a direct replacement for Volvo Penta part number 875796 and earlier versions 833366 and 829812. It is also an interchange for Sierra 18-3665.

Installation: Designed for a direct OEM-style fit.
Operating Temperature: Opens at 60°C (140°F) to regulate engine temperature.
Complete Kit: Includes the thermostat and necessary seals for a full replacement.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.

Brand	Part Number	Superseded By	Notes
Volvo Penta	875796	—	OEM Reference
Sierra	18-3665	—	Aftermarket Interchange
Volvo Penta	833366	875796	Earlier Version
Volvo Penta	829812	875796	Earlier Version

Engine & Model Compatibility

Confirm your engine model and year in the table below.

This kit is compatible with specific Volvo Penta gasoline and diesel sterndrive engines. The gasoline engine range typically covers models produced between 1978 and 1994, while the diesel range covers models from 1975 to 1993.

Brand	Model	Rated HP	Stroke	OEM Part No.	Notes
Volvo Penta	AQ120B	120	4-Stroke	875796	Sterndrive Gasoline Engine
Volvo Penta	AQ125A	125	4-Stroke	875796	Sterndrive Gasoline Engine
Volvo Penta	AQ140A	140	4-Stroke	875796	Sterndrive Gasoline Engine
Volvo Penta	BB140A	140	4-Stroke	875796	Sterndrive Gasoline Engine
Volvo Penta	MB10A		4-Stroke	875796	Sterndrive
Volvo Penta	MD6A		4-Stroke	875796	Marine Diesel Engine
Volvo Penta	MD6B		4-Stroke	875796	Marine Diesel Engine
Volvo Penta	MD7A		4-Stroke	875796	Marine Diesel Engine
Volvo Penta	MD7B		4-Stroke	875796	Marine Diesel Engine
Volvo Penta	MD67C		4-Stroke	875796	Marine Diesel Engine

Technical Specs

Product Type: Thermostat Kit
Installation: Direct OEM Replacement
Temperature Rating: 60°C (140°F)
Operating Temperature: 60°C (140°F) opening temperature
Weight: 0.33 kg (0.73 lb)
Manufacturing Process: ISO 9002 Certified Facility
Warranty: Varies by manufacturer (e.g., Sierra: Limited Lifetime)

What’s in the Box

1 x Thermostat (Replaces OEM 875796)
1 x Seal Ring (Replaces OEM 416033)
1 x O-ring (Replaces OEM 955989)

Installation Notes

Ensure the engine is cool. Disconnect the negative battery terminal for safety.
Place a drain pan under the engine and drain coolant to a level below the thermostat housing.
Locate the thermostat housing, typically where the main coolant hose connects to the engine block.
Remove the bolts securing the housing cover. Note their positions if they are different lengths.
Carefully remove the housing cover. The old thermostat should be visible inside.
Remove the old thermostat and discard the old seal rings and gaskets.
Thoroughly clean the mating surfaces of the housing and its cover to ensure a proper seal.
Install the new thermostat, ensuring it is oriented correctly (the spring side usually faces the engine).
Place the new seal ring and O-ring in their correct positions.
Reinstall the housing cover and tighten the bolts evenly to the manufacturer's specified torque. Do not overtighten.
Refill the cooling system with the appropriate coolant type. Reconnect the battery terminal.
Start the engine, let it warm up, and carefully check for any leaks around the housing. Monitor the temperature gauge to ensure it operates in the normal range.

Troubleshooting & FAQ

Will this thermostat kit fit my specific engine model?

This kit is designed for the Volvo Penta models listed in the Engine & Model Compatibility table. Always cross-reference your engine model and look for OEM part number 875796 in your engine's service manual to guarantee fitment.

How do I know if my current thermostat is failing?

Common signs of a failing thermostat include engine overheating, the engine taking too long to reach operating temperature, erratic temperature gauge readings, or visible coolant leaks around the thermostat housing.

Is this a 140°F or 60°C thermostat?

Both. It is a 60°C thermostat, which is equivalent to 140°F. It is designed to begin opening at this temperature to allow coolant to circulate through the engine block and radiator.

Does this kit include everything I need for the replacement?

Yes, the kit includes the thermostat, a seal ring, and an O-ring. These are the essential components required for a standard replacement. You will need your own tools and fresh coolant.

How often should a marine engine thermostat be replaced?

Replacement interval can vary based on usage and operating conditions (saltwater vs. freshwater). It's good practice to inspect it annually and consider replacing it every 3-5 years as part of preventative maintenance to avoid overheating issues.

Why is a specific temperature rating important?

The temperature rating ensures the engine warms up quickly and then maintains a consistent temperature for optimal fuel efficiency, performance, and reduced engine wear. Using the wrong temperature can lead to poor performance or engine damage.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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