Thermostat Kit – Fits Volvo Penta 4.3L, 5.0L, 5.7L, 7.4L, 8.1L (Replaces 0769578, 3853983, 3852111)

Thermostat Kit – Fits Volvo Penta 4.3L, 5.0L, 5.7L, 7.4L, 8.1L

This thermostat kit is designed for a wide range of Volvo Penta gasoline marine engines, including the 4.3L, 5.0L, and 5.7L V6 series, as well as the 7.4L, 8.1L, and 8.2L V8 Big Block series from 1994 to the present. It is also compatible with OMC Cobra 4.3L, 5.0L, 5.7L, and 5.8L models (1994–1998) and select 80-200 HP models (1968-1969).

This assembly serves as a direct replacement for Volvo Penta and OMC parts, ensuring reliable engine temperature regulation for optimal performance and fuel efficiency.

• Operating Temperature: Opens at 60°C (140°F).
• Installation: Direct OEM-style fit, no modifications required.
• Kit Contents: Includes thermostat, gasket, and O-ring for a complete installation.

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.

Volvo Penta

OMC

Technical Specifications

Package Contents

• 1 x Thermostat (3853983)
• 1 x Gasket (3852111)
• 1 x O-ring (3852071)

Installation Guide

1. Safety First: Ensure the engine is completely cool before beginning. Disconnect the battery.
2. Drain Coolant: Place a catch pan under the engine drain plug and drain the coolant to a level below the thermostat 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 holding the thermostat housing cover. You may need to gently tap it to break the seal.
5. Remove Old Thermostat: Note the orientation of the old thermostat and remove it from the housing.
6. Clean Surfaces: Thoroughly clean the mating surfaces of the housing and cover, removing all old gasket material.
7. Install New Thermostat: Place the new thermostat into the housing in the correct orientation.
8. Install Gasket/O-Ring: Position the new gasket and/or O-ring, ensuring they are properly seated.
9. Reassemble: Re-install the housing cover and tighten the bolts to the manufacturer's specified torque. Do not overtighten.
10. Refill & Check: Refill the cooling system with the appropriate coolant. Reconnect the battery, start the engine, and check for leaks and proper temperature gauge operation.

Troubleshooting & FAQ

Q: How do I confirm this thermostat kit will fit my engine?

A: The best way is to compare your original part number to those listed in our cross-reference table. Additionally, check the Compatible Engine Models tables to ensure your specific model and year are listed. When in doubt, visual comparison is also helpful.

Q: What are the signs of a faulty thermostat?

A: Common symptoms include engine overheating (stuck closed) or the engine failing to reach its normal operating temperature (stuck open), which can lead to poor performance and increased fuel consumption. An erratic temperature gauge reading can also indicate a problem.

Q: At what temperature does this thermostat open?

A: This thermostat is rated to begin opening at 60°C (140°F), which is the standard specification for the listed engine applications.

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.