Thermostat Kit – Fits Volvo Penta AQ165/AQ170/BB165/BB170 Series Marine Engines (Replaces 875791, 831040)

Thermostat Kit – Fits Volvo Penta AQ165/AQ170/BB165/BB170 Series Marine Engines (Replaces 875791, 831040)

This thermostat kit is designed for Volvo Penta AQ165A, AQ170A/B/C, BB165A, and BB170A/B/C marine gasoline engines. It is specifically built for models equipped with the B30 inline 6-cylinder engine from 1965–1978 that use a seawater (raw water) cooling system.

This kit serves as a direct replacement for Volvo Penta OEM part numbers 875791 and 831040, as well as Sierra aftermarket part 18-3663.

• Operating Temperature: Opens at 55°C (131°F) for optimal engine performance in raw water systems.
• Installation: Engineered as a direct-fit OEM replacement.
• Engine Type: Compatible with the Volvo Penta B30 inline 6-cylinder engine.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Thermostat Service Kit (Replaces 875791/831040)

Installation Guide

1. Ensure the engine is completely cool before starting work.
2. Drain the engine coolant to a level below the thermostat housing.
3. Locate and carefully remove the bolts securing the thermostat housing cover.
4. Note the orientation of the old thermostat before removing it from the housing.
5. Remove the old thermostat and gasket. Thoroughly clean the mating surfaces of the housing and cover.
6. Install the new thermostat, making sure it is seated in the correct direction.
7. Position the new gasket and reinstall the housing cover.
8. Tighten the bolts evenly to the manufacturer's recommended torque specification.
9. Refill the cooling system with the appropriate coolant.
10. Start the engine and check for any leaks around the housing as the engine warms up.
11. Monitor the temperature gauge to ensure the engine operates at the correct temperature.

Troubleshooting & FAQ

Q: How do I confirm this thermostat fits my Volvo Penta engine?

A: This kit is designed for Volvo Penta AQ165A, AQ170A/B/C, BB165A, and BB170A/B/C models using the B30 inline 6-cylinder engine (1965–1978). Please verify your model against the "Compatible Engine Models" list and ensure your engine uses a seawater cooling system.

Q: What temperature does this thermostat open at?

A: The thermostat is calibrated to open at 55°C (131°F), which is the standard temperature required for these raw water-cooled marine engines to operate efficiently.

Q: My engine is overheating. Could the thermostat be the problem?

A: A faulty thermostat that is stuck closed is a common cause of engine overheating. If your engine is running too hot, the thermostat may not be opening to allow coolant to circulate. However, also be sure to check for a worn seawater pump impeller or blockages in the cooling lines.

Q: OEM vs. Aftermarket?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.