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Thermostat Kit – Fits Volvo Penta MD2, MD6, MD7 Marine Diesel Engines (Replaces 875796, 833366)

Sale price $79.99 Regular price $127.00
Shipping calculated at checkout.

Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

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 is a direct replacement Thermostat Kit – Fits Volvo Penta MD2, MD6, MD7 Marine Diesel Engines, specifically designed for the MD2, MD6A, MD6B, MD7A, and MD7B series manufactured in the 1970s and 1980s. It ensures your engine maintains the correct operating temperature for optimal performance and longevity.

This kit provides a direct interchange for Volvo Penta part numbers 875796 and 833366, as well as aftermarket references Sierra 18-3665 and ZDCBMDB 875796.

  • Engineered as a direct replacement for straightforward installation.
  • Marine-grade thermostat designed for raw water cooling systems.
  • Includes one complete thermostat service kit.

Part Number Matrix

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

Brand Part Number
Volvo Penta 875796
Volvo Penta 833366
Sierra 18-3665
ZDCBMDB 875796

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This thermostat kit is built for a range of classic Volvo Penta marine diesel engines.

Brand Model Stroke Years OEM Part No. Notes
Volvo Penta MD2 4-Stroke 875796 Diesel marine engine
Volvo Penta MD6A 4-Stroke 1971–1975 875796 Diesel marine engine
Volvo Penta MD6B 4-Stroke 1975–1976 875796 Diesel marine engine
Volvo Penta MD7A 4-Stroke 1976–1981 875796 Diesel marine engine
Volvo Penta MD7B 4-Stroke 1981–1983 875796 Diesel marine engine

Technical Specs

Product Type
Thermostat Kit
Installation
Direct replacement
Fuel Type
Diesel
Connection
Direct fit to housing
Dimensions
30 × 20 × 10 mm (1.18 × 0.79 × 0.39 inches)
Weight
0.05 kg (1.76 ounces)
Fitting Type
Direct fit
Operating Temperature
60°C (140°F) opening temperature
Warranty
Varies by manufacturer (1 year typical for aftermarket)
Other Technical Attributes
Marine-grade thermostat for raw water cooling systems

What’s in the Box

  • 1 x Thermostat Service Kit (875796)

Installation Notes

  1. Ensure the engine is completely cool before starting. Disconnect the negative battery terminal for safety.
  2. Drain engine coolant to a level below the thermostat housing. Have a container ready to catch the fluid.
  3. Locate and carefully unbolt the thermostat housing cover. A light tap may be needed to break the seal.
  4. Note the orientation of the old thermostat before removing it, then remove the gasket.
  5. Thoroughly clean the mating surfaces of both the housing and its cover, removing all old gasket material.
  6. Install the new thermostat in the correct orientation, followed by the new gasket.
  7. Reattach the housing cover and tighten the bolts evenly in a crossing pattern to the manufacturer's specified torque.
  8. Refill the cooling system with the appropriate coolant. Reconnect the battery terminal.
  9. Start the engine, check for any leaks around the housing, and let it warm up to confirm the thermostat opens correctly.

Troubleshooting & FAQ

How do I know if this thermostat fits my engine?

This kit is specifically for Volvo Penta MD2, MD6A, MD6B, MD7A, and MD7B series marine diesel engines. Please verify your exact model and year against the compatibility table provided on this page and compare your old part to our photos.

What are the common signs of a failing thermostat?

Symptoms of a faulty thermostat include engine overheating, the engine not reaching its normal operating temperature (running too cold), erratic temperature gauge fluctuations, or visible coolant leaks from the thermostat housing area.

What is the correct opening temperature for this thermostat?

This thermostat is designed to begin opening at 60°C (140°F) to regulate engine temperature in raw water cooling systems.

Can I install this part myself?

While installation can be performed by individuals with mechanical experience, we recommend professional installation to ensure a proper seal and prevent potential issues like coolant leaks or engine overheating.

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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