160°F Marine Thermostat Kit for MerCruiser, OMC Cobra & Volvo Penta 4.3L–5.8L Engines
160°F Marine Thermostat Kit for MerCruiser, OMC Cobra & Volvo Penta 4.3L–5.8L Engines is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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160°F Marine Thermostat Kit for MerCruiser, OMC Cobra & Volvo P...
160°F Marine Thermostat Kit for MerCruiser, OMC Cobra & Volvo Penta 4.3L–5.8L Engines is backordered and will ship as soon as it is back in stock.
Product Details
This 160°F (71°C) marine thermostat kit is a direct replacement kit for selected MerCruiser, OMC Cobra and Volvo Penta stern-drive and inboard marine engine applications. It is intended for the cooling systems of 4.3L engines, selected 5.0L engines, 5.7L engines except OSi applications, and 5.8L engines.
The kit is also listed for OMC applications through 1993, excluding four-cylinder GM engines using the 1980-and-newer thermostat arrangement. Always compare the thermostat, housing and sealing arrangement on your engine before ordering.
- 160°F (71°C) operating temperature rating.
- Includes the thermostat and the sealing components specified for this kit.
- Aftermarket replacement for listed OEM and aftermarket reference numbers.
- Designed for marine stern-drive and related engine cooling applications.
Part Number References
The following numbers are listed as OEM, manufacturer or aftermarket reference numbers for this application. They are provided for cross-reference only; confirm the complete engine and cooling-system configuration before purchase.
| Reference Type | Part Number |
|---|---|
| MerCruiser | 802259 |
| MerCruiser | 802326 |
| MerCruiser | 45-802326 |
| OMC | 379754 |
| OMC | 383307 |
| OMC | 3852216 |
| OMC | 778056 |
| Volvo Penta | 3852127 |
| Volvo Penta | 3852216 |
| Volvo Penta | 3856961 |
| Aftermarket | 18-3653, 18-3554, 18-3677 |
| Aftermarket | 18-3653D, 18-3677D |
Engine Compatibility
Company fitment information lists the following engine families and model groups. Model, serial-number and cooling-system variations can affect fitment, so verify the existing thermostat and gasket arrangement before installation.
| Brand or Application | Engine / Model Information | Temperature | Fitment Notes |
|---|---|---|---|
| MerCruiser stern-drive | 4.3L, all models | 160°F (71°C) | Confirm the installed housing and seal arrangement. |
| MerCruiser stern-drive | 5.0 FiP, FLP, GiP, GLP, GL, GXi and OSi | 160°F (71°C) | Listed model groups; verify the complete engine configuration. |
| MerCruiser stern-drive | 5.7L | 160°F (71°C) | All models except OSi applications as listed by the company. |
| MerCruiser stern-drive | 5.8L, all models | 160°F (71°C) | Confirm the original thermostat and gasket layout. |
| OMC Cobra / stern-drive | OMC applications through 1993 | 160°F (71°C) | Excludes four-cylinder GM engines using the 1980-and-newer thermostat arrangement. |
| Volvo Penta stern-drive | 4.3L, all models | 160°F (71°C) | Confirm the original housing and sealing components. |
| Volvo Penta stern-drive | 5.0 FiP, FLP, GiP, GLP, GL, GXi and OSi | 160°F (71°C) | Listed model groups; verify the complete engine configuration. |
| Volvo Penta stern-drive | 5.7L, all models except OSi | 160°F (71°C) | Compare the original thermostat before ordering. |
| Volvo Penta stern-drive | 5.8L, all models | 160°F (71°C) | Confirm the original housing and gasket arrangement. |
Technical Specifications
- Product Type
- Marine engine thermostat kit
- Temperature Rating
- 160°F (71°C)
- Application
- Selected MerCruiser, OMC Cobra and Volvo Penta stern-drive and marine engine cooling systems
- Construction
- Thermostat with replacement sealing components
- Installation
- Direct replacement when the listed part number and cooling-system configuration match
- Product Status
- Aftermarket replacement, not an original equipment component
What’s in the Box
- 1 × 160°F thermostat
- 1 × O-ring
- 1 × gasket
- 1 × additional gasket
- 1 × housing gasket
Gasket shapes and component markings may vary by production batch. Match each supplied seal to the original component and the service-manual installation diagram.
Installation Notes
- Allow the engine to cool completely and follow the safety procedures in the engine service manual.
- Disconnect the battery or otherwise isolate the starting system before beginning service.
- Place a suitable drain pan beneath the thermostat housing and manage coolant or water according to the engine’s cooling-system design.
- Remove the thermostat housing fasteners and carefully separate the housing from the engine.
- Note the orientation of the old thermostat and the position of each gasket and O-ring.
- Remove all old sealing material from the mating surfaces without damaging the housing or engine.
- Install the new thermostat in the same orientation as the original part.
- Install the supplied O-ring and gaskets in the locations specified for your exact engine model.
- Reinstall the housing and tighten the fasteners to the torque specified by the engine manufacturer.
- Restore the cooling system as required, reconnect the battery, run the engine according to the service procedure and check for leaks and proper operating temperature.
Troubleshooting & FAQ
How do I confirm that this kit fits my engine?
Compare the original thermostat and housing arrangement with the compatibility information and part-number references above. Check the exact engine model, serial information and cooling-system configuration in the service manual. Do not rely on displacement alone.
What does the 160°F rating mean?
The thermostat is designed to regulate engine coolant or cooling-water flow around 160°F (71°C), subject to the engine’s cooling-system design and operating conditions.
What symptoms can indicate a thermostat problem?
Possible symptoms include overheating, an engine that runs cooler than expected, unstable temperature readings, restricted cooling flow or leakage around the thermostat housing. Inspect the complete cooling system before replacing the thermostat.
Are all of the listed gaskets used on every engine?
The kit includes the sealing components listed by the company, but the exact components used during installation depend on the engine and housing configuration. Follow the service-manual diagram for your specific application.
Is this an OEM thermostat?
No. This is an aftermarket replacement kit. The OEM and aftermarket numbers shown above are reference numbers used to help confirm application and interchange.
Can I use a different thermostat temperature?
Use the temperature rating specified for your engine. Replacing a 160°F thermostat with a different rating can change engine operating temperature and may affect cooling-system performance.
Safety & Important Information
- Never open a hot cooling system. Allow the engine to cool before removing the thermostat housing.
- Verify the original part number, thermostat dimensions, housing style and gasket arrangement before ordering.
- Keep model, serial-number and cooling-system conditions together when confirming fitment.
- Use the engine manufacturer’s service procedures and specified fastener torque.
- Professional installation is recommended if you are unfamiliar with marine engine cooling-system service.
About Sea Sierra
- Marine Replacement Parts — Replacement components for common marine engine and stern-drive service applications.
- Application-Focused Information — Product references and fitment details are provided to support part-number and configuration checks.
- Service-Ready Kits — This kit combines the 160°F thermostat with the listed O-ring and gasket components for a convenient replacement.
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