Thermostat – Fits Volvo Penta MD2030/MD2040/D2 Series (Replaces 3580365/3850365)
Thermostat – Fits Volvo Penta MD2030/MD2040/D2 Series (Replaces 3580365/3850365) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Thermostat – Fits Volvo Penta MD2030/MD2040/D2 Series (Replaces 358...
Product Details
This Thermostat – Fits Volvo Penta MD2030/MD2040/D2 Series is a direct-fit replacement for regulating engine temperature in Volvo Penta D2 and MD2 series diesel engines (30–75 hp) from 1999 to present. It is designed to maintain optimal performance in the specified marine environments.
This component provides a direct interchange for Volvo Penta part numbers 3580365 and 3850365, as well as the Sierra aftermarket equivalent 18-3680.
- Installation Method: Direct OEM-style replacement.
- System Type: Engineered for closed cooling systems.
- Package Contents: Includes thermostat as pictured.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Volvo Penta | 3580365 |
| Volvo Penta | 3850365 |
| Sierra | 18-3680 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Volvo Penta owners, please verify your engine model and year range to ensure correct fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Volvo Penta | MD2030 | 30 | 4-Stroke | 1999–2007 | 3580365/3850365 | All variants (MD2030-A, B, C, D) |
| Volvo Penta | MD2040 | 40 | 4-Stroke | 1999–2007 | 3580365/3850365 | All variants (MD2040-A, B, C, D) |
| Volvo Penta | D2-55 | 55 | 4-Stroke | 2001–Present | 3580365/3850365 | All variants (D2-55A, B, C, D, E, F) |
| Volvo Penta | D2-75 | 75 | 4-Stroke | 2001–Present | 3580365/3850365 | All variants |
Technical Specs
- Product Type
- Thermostat
- Installation
- Direct OEM replacement
- Fuel Type
- Diesel
- Housing Material
- Metal
- Housing Color
- Silver/Metallic
- Dimensions
- 11.0" x 6.7" x 6.0"
- Technical Design
- Designed for closed cooling system
- Warranty
- Manufacturer dependent: Limited Lifetime (Sierra), OEM warranty (Volvo Penta)
What’s in the Box
- 1 x Thermostat (Replaces 3580365/3850365)
Installation Notes
- Ensure the engine is completely cool before starting.
- Drain the engine coolant to a level below the thermostat housing.
- Carefully remove the bolts securing the thermostat housing cover.
- Note the orientation of the old thermostat before removing it from the housing.
- Thoroughly clean the mating surfaces of the housing and cover, removing all old gasket material.
- Install the new thermostat, ensuring it is seated in the correct orientation.
- Position a new gasket and re-install the housing cover, tightening bolts evenly to the manufacturer's specified torque.
- Refill the cooling system with the appropriate coolant mixture.
- Start the engine, check for any leaks, and monitor the temperature gauge to ensure proper operation as it warms up.
Troubleshooting & FAQ
How do I know if my thermostat has failed?
Common signs of a failing thermostat include engine overheating (stuck closed), the engine not reaching operating temperature (stuck open), erratic readings on the temperature gauge, or visible coolant leaks around the thermostat housing.
Is this the correct part for my D2-75F engine?
Yes, this thermostat is compatible with all variants of the Volvo Penta D2-75, including the D2-75F, from its introduction in 2001 to the present. Always cross-reference the part number (3580365/3850365) with your engine's service manual to be certain.
What temperature does this thermostat open at?
While the specific opening temperature is not published, this is a direct replacement for the OEM part and is manufactured to operate within the original factory temperature specifications required by the listed Volvo Penta engines.
Is a gasket included with this thermostat?
This listing is for the thermostat only. Gaskets are sold separately. It is critical to use a new, compatible gasket during installation to ensure a proper seal and prevent coolant leaks.
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.
Payment & Security
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