Water Pump Gasket – Fits Yanmar 2GM, 3GM Series Marine Diesel Engines (Replaces 121000-42052)
Water Pump Gasket – Fits Yanmar 2GM, 3GM Series Marine Diesel Engines (Replaces 121000-42052) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Gasket – Fits Yanmar 2GM, 3GM Series Marine Diesel Engin...
Product Details
This high-quality Water Pump Gasket is designed to create a secure seal for the fresh water pump on Yanmar 2GM, 3GM, and 3HM series marine diesel engines. It ensures reliable, leak-free performance of your engine's cooling system.
It serves as a direct replacement for Yanmar part number 121000-42052.
- Installs between the water pump and the engine block.
- Essential component for the fresh water cooling system.
- Made from durable gasket material to withstand engine heat and coolant pressure.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yanmar | 121000-42052 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This gasket is compatible with a range of Yanmar marine diesel engines listed below.
| Brand | Model | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Yanmar | 2GM(F) | 4-Stroke | 121000-42052 | |
| Yanmar | 2GM20F | 4-Stroke | 121000-42052 | |
| Yanmar | 2GM20F-YEU | 4-Stroke | 121000-42052 | |
| Yanmar | 2GM20FC-YEU | 4-Stroke | 121000-42052 | |
| Yanmar | 3GM(F) | 4-Stroke | 121000-42052 | |
| Yanmar | 3GM30F | 4-Stroke | 121000-42052 | |
| Yanmar | 3GM30F-YEU | 4-Stroke | 121000-42052 | |
| Yanmar | 3GM30FC-YEU | 4-Stroke | 121000-42052 | |
| Yanmar | 3HMF | 4-Stroke | 121000-42052 | |
| Yanmar | 3HM35F | 4-Stroke | 121000-42052 |
Technical Specs
- Product Type
- Fresh Water Pump Gasket
- Installation
- Between water pump and engine block
- Fuel Type
- Diesel
- Material
- Gasket material
- Dimensions (L x W x H)
- 11.0 x 11.0 x 0.1
- System
- Fresh water cooling system component
- Part Warranty
- 6 months
What’s in the Box
- 1x Fresh Water Pump Gasket (Replaces 121000-42052)
Installation Notes
- Ensure the engine is off and cool. Disconnect the negative battery terminal.
- Drain the engine's fresh water cooling system into a suitable container.
- Remove the water pump assembly from the engine block, noting the position of bolts and hoses.
- Carefully remove the old gasket. Thoroughly clean both the engine block and water pump mating surfaces, ensuring they are free of old gasket material, sealant, and debris.
- Position the new gasket onto the engine block. Do not use sealant unless specified by the engine manufacturer.
- Reinstall the water pump assembly, tightening bolts to the manufacturer's recommended torque specifications in a star pattern.
- Reconnect all hoses and clamps securely.
- Refill the cooling system with the appropriate coolant mixture.
- Reconnect the battery terminal, start the engine, and carefully check for any leaks around the gasket and hose connections.
Troubleshooting & FAQ
What are the signs of a failing water pump gasket?
Common signs include coolant leaks from the area between the water pump and engine block, frequent coolant loss without visible hose leaks, and engine overheating.
How do I ensure a good seal with this new gasket?
The key is a clean surface. Both the engine block and the water pump mounting surfaces must be perfectly clean, dry, and free from any old gasket material or corrosion before installing the new gasket.
Should I use sealant with this gasket?
It is generally recommended to install this gasket dry. Using sealant can sometimes cause the gasket to slip or create an uneven seal. Always refer to your specific engine's service manual for final guidance.
How often should I replace the water pump gasket?
The gasket should be replaced any time the water pump is removed for service or replacement. There is no fixed interval, but it is a critical component to renew during cooling system overhauls.
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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