Thermostat Cover Gasket – Fits Johnson/Evinrude/OMC Outboards (Replaces 0321184, 321184)
Thermostat Cover Gasket – Fits Johnson/Evinrude/OMC Outboards (Replaces 0321184, 321184) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Thermostat Cover Gasket – Fits Johnson/Evinrude/OMC Outboards (Repl...
Product Details
This aftermarket Thermostat Cover Gasket is designed for a wide range of Johnson/Evinrude/OMC outboard motors, including models from 5 HP to 235 HP (both 2-stroke and 4-stroke). It creates a reliable seal between the thermostat housing and the engine block, which is essential for maintaining the correct engine operating temperature and preventing coolant leaks.
This part is a direct replacement for Johnson/Evinrude/OMC part numbers 0321184 and 321184.
- Designed to install as a direct factory replacement.
- Forms a secure seal between the thermostat cover and engine block.
- Helps maintain correct engine operating temperature for optimal performance.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Johnson/Evinrude/OMC | 0321184, 321184 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
While this gasket fits a broad range of applications, it is crucial to verify compatibility with your specific outboard motor. This part is designed for various Johnson/Evinrude/OMC models.
| Brand | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Johnson/Evinrude/OMC | 5–235 HP | 2-Stroke & 4-Stroke | 0321184, 321184 | Direct replacement for specified OEM part numbers. |
Technical Specs
- Product Type
- Thermostat Cover Gasket
- Connection
- Thermostat Cover to Engine Block
- Material
- Gasket Material (Paper/Composite)
- Dimensions
- 6.0 in x 7.25 in x 0.13 in
- Weight
- 1 lb (0.45 kg)
- Fitting Type
- Gasket
What’s in the Box
- 1 x Thermostat Cover Gasket (Replaces 0321184, 321184)
Installation Notes
- Ensure the engine is completely cool and disconnect the battery's negative terminal for safety.
- Drain the engine coolant to a level below the thermostat housing.
- Carefully remove the bolts securing the thermostat housing cover. Note their positions if they are different lengths.
- Gently pry off the old cover. Remove the old gasket and any remaining sealant or corrosion from both the cover and the engine block mating surfaces. A plastic scraper is recommended to avoid gouging the metal.
- Place the new thermostat cover gasket onto the clean engine block surface, ensuring it aligns correctly with the bolt holes.
- Reinstall the thermostat housing cover and tighten the bolts in a crisscross pattern to the manufacturer's recommended torque specification. Do not overtighten.
- Refill the cooling system with the appropriate coolant. Start the engine, let it reach operating temperature, and carefully check for any leaks around the housing.
Troubleshooting & FAQ
How can I confirm this gasket fits my specific Evinrude/Johnson outboard?
This gasket replaces OEM part numbers 0321184 and 321184. The best way to ensure a match is to compare your old part's number and shape to the ones shown in our product images. While it fits many models from 5–235 HP, visual verification is crucial.
What are the signs of a failing thermostat cover gasket?
Common symptoms include visible coolant leaks around the thermostat housing, engine overheating or running at an improper temperature, and a low coolant level warning. You may also notice white steam or a sweet smell from the engine compartment.
Should I use sealant or adhesive with this gasket?
Generally, this type of gasket is designed to be installed dry on clean, flat surfaces. Applying sealant can sometimes cause the gasket to slip or create an uneven seal. However, always refer to your specific engine's service manual for the manufacturer's recommendation.
How can I tell if my overheating issue is the gasket or the thermostat itself?
A leaking gasket is usually visible. If there are no leaks but the engine is overheating, the thermostat may be stuck closed. If the engine is running too cold, the thermostat may be stuck open. It is often recommended to replace both the thermostat and its gasket at the same time.
Is this an original OEM part or an aftermarket replacement?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials, and it is manufactured in an ISO 9002 facility and batch-inspected for consistency.
What are the shipping speeds and costs?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free; expedited options will appear at checkout where available for your location.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, 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. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
