Thermostat Repair Service Kit for Volvo Penta 4.3L 5.0L 5.7L V6 V8 SternDrive Motors 3587597

Thermostat Kit for Volvo Penta 4.3L 5.0L 5.7L Engines

This thermostat kit is engineered for Volvo Penta 4.3L, 5.0L, and 5.7L V6 & V8 sterndrive engines, primarily suiting models from the 1990s to early 2000s equipped with a freshwater cooling system.

It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Volvo Penta 3587597 and 3862835, Sierra 18-3618 series, and others, ensuring broad compatibility for maintenance and repair.

• Includes a 150°F (66°C) thermostat, gasket, and O-ring for a complete installation.
• Designed specifically for marine engines with freshwater cooling systems.
• Replaces essential components to restore proper engine operating temperature.

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. Preparation: Ensure the engine is completely cool. Disconnect the negative battery terminal for safety.
2. Drain Coolant: Place a drain pan under the thermostat housing and drain the coolant to a level below the housing.
3. Locate Housing: Find the thermostat housing, typically where the main coolant hose from the circulation pump connects to the engine block.
4. Remove Housing: Loosen and remove the bolts securing the housing cover. Gently tap the housing if it's stuck, but avoid prying.
5. Remove Old Thermostat: Lift out the old thermostat and note its orientation.
6. Clean Surfaces: Thoroughly clean the mating surfaces of the housing and engine block, removing all old gasket material and corrosion.
7. Install New Thermostat: Place the new thermostat into the block or housing in the correct orientation.
8. Install Gasket/O-Ring: Position the new gasket and O-ring, ensuring they are seated correctly to prevent leaks.
9. Reattach Housing: Reinstall the housing cover and tighten the bolts evenly to the manufacturer's recommended torque specifications.
10. Refill Coolant: Refill the cooling system with the appropriate type and amount of coolant.
11. Check for Leaks: Reconnect the battery. Start the engine and let it warm up, carefully checking for any leaks around the thermostat housing.
12. Final Check: Once the engine reaches operating temperature, check the coolant level again and top off if necessary.

Troubleshooting & FAQ

How do I know if this thermostat kit will fit my Volvo Penta engine?
This kit is designed for Volvo Penta 4.3L, 5.0L, and 5.7L V6 & V8 sterndrive engines, mainly from the 1990s to early 2000s using freshwater cooling. Please review the "Compatible Engine Models" table and cross-reference your OEM part number to ensure a match.

What are the signs of a failing thermostat?
Common signs include engine overheating, the engine not reaching normal operating temperature, or erratic temperature gauge readings. A stuck-open thermostat will prevent the engine from warming up, while a stuck-closed one will cause it to overheat quickly.

Is this a 150°F or a different temperature thermostat?
This is a 150°F (66°C) thermostat. Using the correct temperature rating is critical for ensuring optimal engine performance, fuel efficiency, and longevity, especially in freshwater-cooled marine applications.

OEM vs. Aftermarket?
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.

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

What is your warranty and return policy?
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.