Marine Thermostat Kit – Fits OMC Cobra 120/140HP & Volvo Penta 2.5L/3.0L (Replaces 3853799, 982554)

Marine Thermostat Kit – Fits OMC Cobra 120/140HP & Volvo Penta 2.5L/3.0L

This marine thermostat kit is designed for OMC 2.5L and 3.0L (120/140 HP) stern drive engines from 1968 and newer. It is also compatible with Volvo Penta 3.0L stern drive engines manufactured from 1996 and newer.

This assembly provides a direct replacement for several OEM and aftermarket part numbers, ensuring a reliable fit for your engine's cooling system. It includes the thermostat and all necessary gaskets for a complete installation.

• Maintains proper engine operating temperature at 160°F (71°C).
• Engineered as a direct-fit replacement for the original thermostat assembly.
• Kit includes one thermostat and two gaskets 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.

OMC

Volvo Penta

Technical Specifications

Package Contents

• 1 x Thermostat (3853799)
• 1 x Thermostat Housing Gasket (0314809)
• 1 x Thermostat Gasket (0313416)

Installation Guide

1. Ensure the engine is cool and disconnect the battery for safety.
2. Drain the engine coolant to a level below the thermostat housing.
3. Loosen and remove the bolts or nuts securing the thermostat housing cover.
4. Carefully lift the housing, taking note of the thermostat's orientation.
5. Remove the old thermostat and discard the old gaskets from the mating surfaces.
6. Thoroughly clean both the housing and the engine block mating surfaces.
7. Install the new thermostat in the correct orientation (spring-side towards the engine block).
8. Place the new gaskets on the cleaned surfaces as required.
9. Re-seat the thermostat housing and tighten the bolts evenly to the manufacturer's specified torque.
10. Refill the cooling system with the correct type and amount of coolant.
11. Reconnect the battery, start the engine, and carefully check for any leaks around the housing as the engine warms up.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my engine?

A: This kit fits specific OMC (1968+) and Volvo Penta (1996+) models. The best way to confirm is to match your engine's model and year to the "Compatible Engine Models" table and verify your old part number against our "Part Number Cross-Reference" list. When in doubt, compare the product photos to your existing part.

Q: What are the signs of a failing thermostat?

A: Common symptoms include the engine overheating, the engine not reaching its proper operating temperature (running too cold), erratic temperature gauge readings, and coolant leaks from the thermostat housing area.

Q: What is the operating temperature of this thermostat?

A: This thermostat is rated to open at 160°F (71°C), which is the standard specification for the intended marine applications to ensure optimal engine performance and efficiency.

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.