Thermostat Kit 160°F – Fits OMC Cobra & Volvo Penta 3.8L-7.5L V6/V8 (Replaces 383307, 3856961)
Thermostat Kit 160°F – Fits OMC Cobra & Volvo Penta 3.8L-7.5L V6/V8 (Replaces 383307, 3856961) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
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Thermostat Kit 160°F – Fits OMC Cobra & Volvo Penta 3.8L-7.5L V...
Thermostat Kit 160°F – Fits OMC Cobra & Volvo Penta 3.8L-7.5L V6/V8 (Replaces 383307, 3856961) is backordered and will ship as soon as it is back in stock.
Product Details
This Marine Thermostat Kit 160°F is a complete replacement kit for OMC Cobra and Volvo Penta marine engines. It includes a 160°F (71°C) thermostat and all gaskets necessary for installation on V6 and V8 engines, including OMC Cobra models from 1969–1988 (3.8L-7.5L) and various Volvo Penta 4.3L, 5.0L, 5.7L, and 5.8L sterndrive models.
This kit serves as a direct cross-reference for OMC parts 379754, 383307, 3852216, 3856961; Volvo Penta 3856961; Sierra 18-3653/18-3554; GLM 13430/13060; and Mallory 9-43156/9-43021.
- Engineered for direct OEM-replacement fitment.
- Maintains a consistent 160°F (71°C) operating temperature.
- Includes thermostat and all required gaskets for a complete installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| OMC | 379754 |
| OMC | 383307 |
| OMC | 3852216 |
| OMC | 3856961 |
| Volvo Penta | 3856961 |
| Sierra | 18-3653 |
| Sierra | 18-3554 |
| GLM | 13430 |
| GLM | 13060 |
| Mallory | 9-43156 |
| Mallory | 9-43021 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits a wide range of OMC Cobra Sterndrive and Marine Engines produced between 1969 and 1988.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| OMC | 3.8L | 80-120 | 4-Stroke | 1981–1985 | 383307 | Small thermostat version |
| OMC | 4.3L | 120-205 | 4-Stroke | 1985–1986 | 383307 | Small thermostat version |
| OMC | 5.0L | 140-230 | 4-Stroke | 1982–1988 | 383307 | Small thermostat version |
| OMC | 5.7L | 175-260 | 4-Stroke | 1982–1988 | 383307 | Small thermostat version |
| OMC | 7.5L | 320-330 | 4-Stroke | 1982–1988 | 383307 | Small thermostat version |
| OMC | 90 | 90 | 4-Stroke | 1970 | 383307 | Outdrive model |
| OMC | 100 | 100 | 4-Stroke | 1972–1973 | 383307 | Outdrive model |
| OMC | 120 | 120 | 4-Stroke | 1969–1980 | 383307 | Outdrive model |
| OMC | 140 | 140 | 4-Stroke | 1973–1980 | 383307 | Outdrive model |
| OMC | 155 | 155 | 4-Stroke | 1969–1972 | 383307 | Outdrive model |
| OMC | 165-175 | 165-175 | 4-Stroke | 1972–1977 | 383307 | Outdrive models |
| OMC | 185-200 | 185-200 | 4-Stroke | 1978–1981 | 383307 | Outdrive models |
| OMC | 210-245 | 210-245 | 4-Stroke | 1969–1975 | 383307 | Outdrive models |
| OMC | 250-260 | 250-260 | 4-Stroke | 1970–1981 | 383307 | Outdrive models |
| OMC | 305-454 | 305-454 | 4-Stroke | 1977–1982 | 383307 | Outdrive models |
Compatible with various Volvo Penta Four-Stroke V6 and V8 marine engines.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Volvo Penta | 4.3GL/GS/Gi | 140-225 | 4-Stroke | 3856961 | V6 Engine |
| Volvo Penta | 5.0FL/Fi | 170-220 | 4-Stroke | 3856961 | V8 Engine |
| Volvo Penta | 5.7GL/Gi | 200-280 | 4-Stroke | 3856961 | V8 Engine |
| Volvo Penta | 5.8FL/Fi/FSi | 200-300 | 4-Stroke | 3856961 | V8 Engine |
| Volvo Penta | V6-200/225/225E | 200-225 | 4-Stroke | 3856961 | V6 Engine |
| Volvo Penta | V8-225/270/300/320/380 | 225-380 | 4-Stroke | 3856961 | V8 Engine |
Technical Specs
- Product Type
- Marine Engine Thermostat Kit
- Temperature Rating
- 160°F (71°C)
- Installation
- Direct OEM replacement
- Housing Color
- Silver/metallic
- Weight
- 2.82 oz (0.08 kg)
- Application
- Small thermostat applications in OMC and Volvo Penta engines
- Production Standard
- ISO9002 certified factory
- Warranty
- Manufacturer warranty (varies by supplier)
What’s in the Box
- 1 x Thermostat (383307)
- 1 x O-ring (3852071)
- 1 x Gasket (314809)
- 1 x Gasket (313416)
- 1 x Housing Gasket (3852111)
- 1 x Installation Instructions (when included by manufacturer)
Installation Notes
- Disconnect the battery terminals to ensure safety.
- Place a catch pan under the engine and drain the coolant below the level of the thermostat housing.
- Locate the thermostat housing and remove the bolts or nuts securing it.
- Gently tap the housing to break the seal and remove it. Take note of the old thermostat's orientation.
- Remove the old thermostat and all gasket material from both the housing and the engine mating surfaces.
- Install the new thermostat in the correct orientation.
- Place the new gaskets and O-rings as required by your specific engine model.
- Reinstall the thermostat housing and tighten the fasteners to the manufacturer's recommended torque.
- Refill the cooling system with the appropriate coolant mixture.
- Reconnect the battery, start the engine, and let it warm up. Check carefully for any leaks around the housing.
Troubleshooting & FAQ
How do I confirm this thermostat fits my engine?
The best way is to cross-reference your existing part number with our Part Number Matrix. Additionally, check your engine model and year against the compatibility tables. If you are unsure, please consult your service manual or a professional marine mechanic.
What are the signs of a faulty thermostat?
Common symptoms include engine overheating (reading high on the temp gauge), the engine not reaching operating temperature (running too cool), or large, sudden fluctuations in temperature. Leaking coolant around the thermostat housing is also an indicator.
Can I use a different temperature thermostat?
It's highly recommended to use the temperature rating specified by your engine's manufacturer (160°F for this kit). Using a hotter or colder thermostat can affect engine performance, fuel efficiency, and longevity.
How often should a marine thermostat be replaced?
Thermostats don't have a fixed replacement interval, but they are a common wear item. It is good practice to inspect them during routine cooling system service or replace them every few hundred hours or every few years, especially if operating in saltwater.
Is this an OEM part?
This is a high-quality aftermarket replacement, not an OEM component. It is designed and manufactured to meet or exceed OEM specifications for fit, form, and function, produced in an ISO 9002 certified facility to ensure quality and reliability.
What are your shipping speeds and costs?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most orders, with expedited options available at checkout where applicable.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for items that are unused and in their original condition.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model is listed as compatible—do not order.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is highly recommended for safety, performance, and to prevent engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world reliability.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with an average transit time of 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
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