Thermostat Repair Kit – Fits Volvo Penta 4.3L 5.0L 5.7L V6/V8 SternDrive (Replaces 3587597, 3862835)

Thermostat Repair Kit – Fits Volvo Penta 4.3L, 5.0L, 5.7L V6/V8 SternDrive

This thermostat repair kit is designed for Volvo Penta 4.3L, 5.0L, and 5.7L V6 & V8 SternDrive engines. It is compatible with OSi/OSXi models from 2001–2003 and all other specified models from 2002 and up using freshwater-cooled systems. It fits a wide range of model designations, including V6-200, V6-225, V8-270, V8-300, and more.

The kit serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility and a precise fit for your marine engine's cooling system.

• Engineered for a 150°F (66°C) opening temperature, crucial for maintaining optimal engine performance.
• Installation is a direct replacement for the factory thermostat, requiring no modifications.
• Kit includes a new thermostat, housing gasket, and O-ring for a complete service.

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 (3587597)
• 1 x Thermostat Housing Gasket (3701777)
• 1 x O-Ring (3852071)

Installation Guide

1. Ensure the engine is completely cool before starting. Disconnect the battery for safety.
2. Locate the thermostat housing on the engine. Place a container underneath to catch any residual coolant.
3. Carefully drain the coolant from the system by opening the designated drain plugs.
4. Remove the bolts securing the thermostat housing cover. You may need to gently tap the cover to break the seal.
5. Note the orientation of the old thermostat before removing it from the housing.
6. Remove the old gasket or O-ring and thoroughly clean both mating surfaces of the housing and cover. Ensure they are free of old gasket material and corrosion.
7. Install the new thermostat in the correct orientation. Confirm it is seated properly in the housing.
8. Place the new gasket and/or O-ring into position on the housing.
9. Reinstall the housing cover and tighten the bolts to the manufacturer's specified torque in a crossing pattern. Do not overtighten.
10. Close the drain plugs and refill the cooling system with the appropriate coolant mixture.
11. Reconnect the battery. Start the engine and let it warm up, carefully checking for any leaks around the thermostat housing.
12. Top off the coolant level once the engine has reached operating temperature and all air has been purged from the system.

Troubleshooting & FAQ

Q: How do I confirm this thermostat kit will fit my specific Volvo Penta engine?
A: The most reliable method is to check your engine's model and year against the "Compatible Engine Models" table on this page. This kit is designed for specific 4.3L, 5.0L, and 5.7L models from 2001 onwards. You can also verify by matching your existing part number with those listed in the "Part Number Cross-Reference" table.

Q: What are the signs of a failing thermostat?
A: Common symptoms include engine overheating (temperature gauge reading higher than normal) or the engine failing to reach its proper operating temperature (running too cool). Fluctuating temperature readings or coolant leaks around the thermostat housing can also indicate a problem.

Q: Why is the 150°F (66°C) temperature rating important?
A: The temperature rating ensures your engine warms up quickly and maintains its optimal operating temperature. Using the correct temperature thermostat is critical for engine performance, fuel efficiency, and longevity, especially in a freshwater-cooled system.

Q: How often should I replace my engine's thermostat?
A: There is no strict replacement interval, but it is good practice to inspect it during regular cooling system service or replace it as a preventative measure every few years, especially if operating in harsh marine environments. It should be replaced immediately if you notice any signs of failure.

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.