Description
140°F Thermostat KitFits OMC Cobra/Volvo Penta 7.4L/8.1L/8.2L V6/V8
This marine thermostat kit is designed for OMC Cobra and Volvo Penta stern drives with 7.4L, 8.1L, and 8.2L engines (1993-current). It is engineered to maintain a consistent engine operating temperature of 140°F (60°C) for optimal performance and longevity.
This kit serves as a direct replacement for OMC part numbers 3853983, 312797, and 307239, as well as Volvo Penta numbers 3853983, 3852071, and 835417.
- Operating Temperature: Maintains a stable 140°F (60°C).
- Engine Compatibility: Fits select OMC Cobra and Volvo Penta V6/V8 engines.
- Complete Assembly: Includes the thermostat, gasket, and O-ring for a full replacement.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| OMC | 3853983 |
| OMC | 312797 |
| OMC | 307239 |
| Volvo Penta | 3853983 |
| Volvo Penta | 3852071 |
| Volvo Penta | 835417 |
| Sierra | 18-3676 |
| Mallory | 9-43026 |
Compatible Engine Models
Confirm your engine model/year in the table below.
OMC/Cobra
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| OMC | 7.4L | All | 4-Stroke | 1994-1998 | 3853983 |
| OMC | 8.2L | All | 4-Stroke | 1998 | 3853983 |
Volvo Penta
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Volvo Penta | 7.4L (all models) | Various | 4-Stroke | 1993-current | 3853983 |
| Volvo Penta | 8.2L (all models) | Various | 4-Stroke | 1993-current | 3853983 |
Technical Specifications
| Specification | Value |
|---|---|
| Product Type | Marine Engine Thermostat Kit |
| Installation | Engine Mounted |
| Fuel Type | Gasoline |
| Connection | Direct Engine Mount |
| Housing Material | Marine Grade Material |
| Temperature Rating | 140°F (60°C) |
| Operating Temperature | 140°F (60°C) |
| Other Technical Attributes | For fresh water and salt water cooled engines |
Package Contents
- 1 x Thermostat (3853983, 09886506)
- 1 x Thermostat Gasket (835417, 18-0398)
- 1 x O-Ring (3852071, 18-7170)
Installation Guide
- Ensure the engine is completely cool before starting.
- Drain the engine coolant into a suitable container.
- Locate the thermostat housing on the engine block.
- Carefully remove the bolts securing the housing.
- Remove the old thermostat and gasket. Note the orientation of the thermostat.
- Clean both the housing and engine mounting surfaces thoroughly.
- Install the new gasket and thermostat in the correct position. The spring side usually faces the engine.
- Replace the thermostat housing and tighten the bolts to the manufacturer’s specified torque.
- Refill the cooling system with the appropriate coolant.
- Start the engine and check for leaks around the housing as the engine warms up.
- Once the engine reaches operating temperature, top off the coolant level if necessary.
Troubleshooting & FAQ
Q: How do I confirm this thermostat kit will fit my engine?
A: The best way is to verify your engine model and year against the “Compatible Engine Models” chart. You can also match the part numbers listed in the “Part Number Cross-Reference” table with your existing thermostat or service manual.
Q: What are the symptoms of a faulty thermostat?
A: Common signs include the engine overheating (running too hot) or failing to reach its normal operating temperature (running too cold). Both can negatively impact performance and fuel economy.
Q: Is this thermostat for raw water or freshwater cooling systems?
A: This kit is suitable for both fresh water and salt water cooled engines.
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 shippingtypically 515 days worldwideand 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 existeven if your model is listeddo 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 515 days.
- Direct from Manufacturer: Competitive pricing without compromising quality.
