Thermostat Gasket – Fits Yanmar 3TNE/4TNE & 3TNV/4TNV Series (Replaces 129150-49811)
Thermostat Gasket – Fits Yanmar 3TNE/4TNE & 3TNV/4TNV Series (Replaces 129150-49811) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Thermostat Gasket – Fits Yanmar 3TNE/4TNE & 3TNV/4TNV Series (R...
Product Details
This high-quality Thermostat Gasket – Fits Yanmar 3TNE/4TNE & 3TNV/4TNV Series ensures a reliable seal between the thermostat and its housing. It is engineered for a precise fit on a range of Yanmar industrial and marine engines, including the 3TNE84, 4TNE84, 3TNE88, 4TNE88, 3TNV88, and 4TNV88 models.
This part is a direct replacement for Yanmar OEM part numbers 129150-49811 and the superseded 129470-49810.
- Made from heat-resistant elastomer for durability in marine and industrial environments.
- Designed for direct, hassle-free installation as an O-ring style seal.
- Ensures a proper seal to prevent coolant leaks and maintain engine temperature.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yanmar | 129150-49811 | |
| Yanmar | 129470-49810 | Superseded by 129150-49811 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This component is designed for use in various Yanmar industrial engines. Please check your specific model and part number requirements.
| Brand | Model | OEM Part No. |
|---|---|---|
| Yanmar | 3TNE84 | 129150-49811 |
| Yanmar | 4TNE84 | 129150-49811 |
| Yanmar | 4TNE84T | 129150-49811 |
| Yanmar | 3TNE88 | 129150-49811 |
| Yanmar | 4TNE88 | 129150-49811 |
| Yanmar | 3TNV82A | 129150-49811 |
| Yanmar | 3TNV88 | 129150-49811 |
| Yanmar | 4TNV88-BDHQ | 129150-49811 |
| Yanmar | 4TNV88-BDHQ(T) | 129150-49811 |
| Yanmar | 4TNV88-BDSA | 129150-49811 |
| Yanmar | 4TNV88-BDSA(T) | 129150-49811 |
| Yanmar | 4TNV88-BDSAC | 129150-49811 |
| Yanmar | 4TNV88-BDSA2 | 129150-49811 |
| Yanmar | 4TNV88-BDSA2T | 129150-49811 |
| Yanmar | 4TNV88-BDWI | 129150-49811 |
| Yanmar | 4TNV88-BDYE | 129150-49811 |
| Yanmar | 4TNV88-BNYE883 | 129150-49811 |
| Yanmar | 4TNV88-BNYE883T | 129150-49811 |
| Yanmar | 4TNV88-BPHB | 129150-49811 |
| Yanmar | 4TNV88-GNP | 129150-49811 |
| Yanmar | 4TNV88-XMS | 129150-49811 |
Technical Specs
- Product Type
- Thermostat Gasket/O-Ring
- Installation
- Direct Replacement
- Connection
- Between Thermostat and Housing
- Housing Material
- Rubber/Elastomer
- Housing Color
- Black
- Dimensions
- 4.5" L x 4.5" W x 0.1" H
- Fitting Type
- O-Ring Style
- Other Technical Attributes
- Heat-resistant elastomer material designed for marine/industrial applications
What’s in the Box
- 1 x Thermostat Gasket/O-Ring (129150-49811)
Installation Notes
- Ensure the engine is completely cool before starting.
- Drain the engine coolant to a level below the thermostat housing.
- Carefully remove the nuts/bolts securing the thermostat housing cover.
- Remove the old housing, thermostat, and gasket. Note their orientation.
- Thoroughly clean both the engine and housing mating surfaces to remove all old gasket material and corrosion.
- Position the new thermostat and gasket correctly. Do not use any additional sealant unless specified by the engine manufacturer.
- Reinstall the housing and tighten the fasteners to the torque specified in your service manual.
- Refill the cooling system with the appropriate coolant, and run the engine to check for any leaks.
Troubleshooting & FAQ
How do I know if my thermostat gasket is failing?
Signs of a failing gasket include coolant leaking from the thermostat housing area, engine overheating, or erratic temperature gauge readings. A visual inspection might show a cracked, brittle, or deformed gasket.
Is this a direct fit for a Yanmar 4TNV88 engine?
Yes, this gasket is designed to be compatible with Yanmar 4TNV88 series engines and their variants. To ensure a perfect match, always confirm that part number 129150-49811 is correct for your specific engine model by checking your service manual.
Can I reuse my old gasket after a repair?
No. This gasket is a single-use, crush-type seal. Reusing an old gasket will almost certainly lead to coolant leaks and potential engine damage.
When should this gasket be replaced?
It is best practice to replace the thermostat gasket anytime the thermostat is replaced or when performing significant service on the cooling system to ensure a fresh, 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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