Reliable engine temperature control is critical for heavy-duty machinery. The 129155-49801 (also searched as 12915549801) is a precision-engineered thermostat designed to maintain optimal thermal balance in Yanmar industrial diesel engines. Whether you are performing a routine maintenance check or a complete engine overhaul, ensuring your cooling system uses an OEM-standard replacement is the only way to prevent costly overheating issues.
Directly compatible with a wide range of equipment including mini excavators, generators, and tractors powered by Yanmar 3TNE84, 3TNV88, 4TNV88, 4TNV94, and 4TNV98 series engines. Our stock is ready for immediate global shipping.
| Detail Field | Product Information |
|---|---|
| Part Number | 129155-49801 / 12915549801 |
| Applicable Models | Yanmar 3TNV84, 3TNV88, 4TNV84, 4TNV88, 4TNV94, 4TNV94L, 4TNV98, 4TNV98T |
| Product Name | Engine Water Cooling Thermostat (71°C / 160°F) |
| Condition | Brand New, OEM Standard Replacement |
| Application | Excavators, Forklifts, Marine Engines, Agricultural Equipment overhaul |
| Stock Status | In Stock / Fast Dispatch within 24 Hours |
| Payment Terms | T/T, Western Union, MoneyGram |
| Delivery Methods | Express: DHL, Fedex, EMS, UPS, Air or Sea Freight |
Not all aftermarket parts are created equal. Below is a comparison of our premium replacement versus standard low-cost alternatives found in the market.
| Core Purchasing Points | Our Premium OEM-Standard | Common Market Grades |
|---|---|---|
| 1. Temperature Precision | Strict 71°C Opening Calibration | Loose tolerance (+/- 5-10°C) |
| 2. Material Quality | High-grade Copper & Stainless Steel | Mixed Alloys prone to corrosion |
| 3. Seal Integrity | Included high-temp resistant gasket | Often missing or low-grade rubber |
| 4. Service Life | Tested for 5,000+ thermal cycles | Uncertain, high failure rate |
| 5. Fitment Guidance | Verified against 129155-49801 specs | Generic "one size fits all" approach |
| 6. Fleet Reliability | Trusted by global repair shops | Retail-only, no fleet verification |
Q1: What are the signs of a failing 129155-49801 thermostat in a Yanmar 4TNV98 engine?
A1: Common symptoms include engine overheating shortly after starting, or conversely, the engine failing to reach operating temperature (running too cold). If you notice the coolant temperature gauge fluctuating wildly during excavator operation, it is time to inspect the thermostat for sticking.
Q2: Can I use this part for a Yanmar 3TNV88 engine rebuild?
A2: Yes, the 129155-49801 is the standard cooling component for 3TNV88 engines. For a complete overhaul, we recommend replacing the thermostat along with the water pump and head gasket set to ensure long-term reliability.
Q3: Why Choose This Engine Thermostat?
A3: It features an OEM-standard tri-metal structure. Our parts are trusted by repair shops and equipment fleets worldwide for their consistent performance in harsh environments.
Not sure how this issue affects your equipment?
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✔ Identify potential risks during maintenance
✔ Recommend suitable replacement parts if needed
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