Engine Block Drain Plug Kit – Fits MerCruiser (Replaces 22-806608A02, 18-4226)
Engine Block Drain Plug Kit – Fits MerCruiser (Replaces 22-806608A02, 18-4226) is backordered and will ship as soon as it is back in stock.
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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).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Engine Block Drain Plug Kit – Fits MerCruiser (Replaces 22-806608A0...
Product Details
This Engine Block Drain Plug Kit contains blue, wing-nut style drain plugs for draining engine cylinder blocks and exhaust manifolds on most MerCruiser stern drive and inboard engines. Designed for easy, hand-tightened installation, they provide a reliable seal to protect your engine during winterization and maintenance.
These plugs are a direct replacement for MerCruiser part numbers 22-806608A02 and Sierra 18-4226, also serving as an interchange for GLM 13992 and Mallory 9-41203.
- Installs easily by hand with its wing-nut design.
- Made from durable blue nylon plastic.
- Includes the necessary O-ring for a complete seal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Sierra | 18-4226 |
| MerCruiser | 22-806608A02 / 22-806608A1 / 22-8M0119211 |
| GLM | 13992 |
| Mallory | 9-41203 / 9-41203-10 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | OEM Part No. | Notes |
|---|---|---|---|
| MerCruiser | Various Stern Drive and Inboard Engines | 22-806608A02/22-806608A1/22-8M0119211 | Fits cylinder blocks and exhaust manifolds |
Technical Specs
- Product Type
- Engine Block & Manifold Drain Plug
- Installation
- Hand-tightened (Wing nut style)
- Housing Material
- Plastic (Nylon)
- Housing Color
- Blue
- Weight
- 0.63 oz (17.9 g)
- Fitting Type
- Drain Plug
- Thread Size
- 0.500-13 (1/2"-13)
- Warranty
- Limited lifetime (Sierra brand)
- Other Technical Attributes
- O-ring seal included
What’s in the Box
- 5 x Closed Cooling Drain Plugs (22-806608A02)
- 5–10 x O-Rings (dependent on package)
Installation Notes
- Ensure the engine is off and completely cool before starting.
- Locate the existing drain plugs on the engine block and/or exhaust manifolds. Place a drain pan underneath to catch any fluid.
- Unscrew the old plugs by hand. They should not require tools if installed correctly.
- Clean the threaded port and surrounding surface to ensure a clean mating area.
- Place a new O-ring onto each new drain plug.
- Thread the new plugs into the ports and hand-tighten until snug. Do not use tools or overtighten, as this can damage the plug or engine block.
- After installation, refill the cooling system according to your engine's service manual.
- Run the engine for several minutes and carefully check for any leaks around the new plugs.
Troubleshooting & FAQ
How do I know if these plugs fit my MerCruiser engine?
These plugs are compatible with most MerCruiser stern drive and inboard engines that require part number 22-806608A02. The most reliable method is to check your service manual or confirm the part number on your old plugs before ordering.
What is the correct way to install these drain plugs?
These are designed to be hand-tightened only. The wing-nut head provides sufficient leverage for a proper seal. Using wrenches or other tools can crack the plastic housing or damage the O-ring, leading to leaks.
Why is my new drain plug leaking?
A leak is typically caused by three things: an improperly seated or damaged O-ring, debris on the engine's sealing surface, or overtightening. Remove the plug, check that the O-ring is in good condition and correctly positioned, clean the threaded hole, and reinstall by hand until just snug.
How often should these plastic drain plugs be replaced?
Inspect your drain plugs annually, typically during winterization or spring commissioning. Replace them immediately if you notice any signs of cracking, brittleness, deformation, or if the O-ring seal appears compressed or damaged.
What are the signs of a failing drain plug?
The most common sign is a persistent coolant or water drip from the plug's location. Visual signs include cracks in the plastic, especially around the threads or wing-nut, or an inability to tighten snugly by hand.
Can I re-use the O-ring from my old plug?
It is strongly recommended to always use the new O-ring supplied with the plug. Old O-rings can become compressed, brittle, or cracked, and will not provide a reliable seal.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in 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
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