4D84 4D88 Thermostat 129155-49801 129155-49800 for Yanmar Engine Parts

Product Details

Product Overview

This high-quality thermostat, identified by OEM part numbers 129155-49801 and 129155-49800, is a direct replacement component specifically designed for Yanmar diesel engines. It is commonly used in the Yanmar 4D84 and 4D88 engine models, which power a wide range of heavy equipment and industrial machinery.

As a critical part of the engine’s cooling system, this thermostat ensures the engine reaches its optimal operating temperature quickly and maintains it consistently. This prevents overheating, reduces engine wear, and improves fuel efficiency. The part is manufactured to meet OEM specifications, ensuring a precise fit and reliable performance.

Key Features & Benefits

• Precise Temperature Control: Designed to open and close at the correct temperature, ensuring the engine operates within the ideal thermal range for maximum efficiency and longevity.
• OEM Standard Fitment: Manufactured to the exact dimensions and specifications of the original Yanmar part, guaranteeing a direct, hassle-free installation without modifications.
• Durable Construction: Built with high-quality, corrosion-resistant materials to withstand the harsh operating conditions of construction, agricultural, and marine environments.
• Enhanced Engine Protection: Prevents cold running (which causes sludge and wear) and overheating (which can cause severe engine damage), extending the life of your Yanmar diesel engine.
• Reliable Performance: Undergoes rigorous quality checks to ensure consistent operation and long service life, reducing downtime and maintenance costs.
• Cost-Effective Solution: A high-quality aftermarket alternative to expensive dealer parts, offering exceptional value without compromising on performance or reliability.

Technical Specifications

OEM Cross-Reference

This thermostat is a direct replacement for the following original Yanmar part numbers:

• 129155-49800
• 129155-49801

If your original part bears either of these numbers, this unit is the correct replacement. Please verify your existing part number before ordering to ensure compatibility.

Compatibility

This thermostat is specifically designed for use in Yanmar diesel engines, particularly the 4D84 and 4D88 models. These engines are commonly found in the following applications:

• Compact Excavators (e.g., Yanmar B series, VIO series)
• Wheel Loaders
• Agricultural Tractors
• Generator Sets (Gensets)
• Marine Propulsion Engines
• Industrial Material Handling Equipment

Note: This part is commonly used for the applications listed above. We recommend cross-referencing your engine model and serial number to confirm fitment before purchase.

Global Supply & Distribution

We maintain a robust global supply chain to serve international B2B buyers efficiently. Our inventory is strategically managed to ensure fast and reliable delivery to major markets worldwide, including:

• North America: USA, Canada, Mexico
• Europe: Germany, France, UK, Netherlands, Italy, Spain
• Asia-Pacific: Japan, Australia, South Korea, Southeast Asia
• Middle East & Africa: UAE, Saudi Arabia, South Africa, Nigeria
• South America: Brazil, Argentina, Chile, Peru

We offer fast shipping to major ports and industrial hubs. Our team has extensive experience in international trade, customs documentation, and logistics, ensuring a smooth transaction for our partners.

Quality Assurance

Every thermostat undergoes a rigorous quality control process to ensure it meets our high standards for performance and reliability.

• Manufacturing Standards: Parts are produced in ISO-certified facilities, adhering to strict quality management systems.
• Testing: Each unit is functionally tested for opening temperature, lift height, and sealing pressure to ensure OEM-level performance.
• Inspection: We provide Video Outgoing Inspection and Machinery Test Reports upon request, giving you full visibility into the product quality before shipment.
• Warranty: All parts come with a standard 6-month warranty against manufacturing defects. After-warranty service and online technical support are also available.

FAQ

Q: How do I know if this thermostat (129155-49801) fits my Yanmar engine?

A: First, locate the part number on your existing thermostat. It is usually stamped into the metal body. If it matches 129155-49800 or 129155-49801, this unit is a direct replacement. Additionally, ensure your engine model is a Yanmar 4D84 or 4D88. If you are unsure, please contact us with your engine serial number for verification.

Q: What is the correct installation procedure for a new thermostat?

A: Installation is straightforward. First, drain the coolant to below the thermostat housing level. Remove the housing bolts, clean the mating surfaces thoroughly, and install the new thermostat with the jiggle valve (if present) facing upwards. Use a new gasket and apply a thin layer of sealant if required. Re-torque the housing bolts to the manufacturer’s specification, refill with coolant, and bleed the air from the system. Always run the engine and check for leaks after installation.

Q: What are the signs that my Yanmar engine thermostat needs to be replaced?

A: Common symptoms include: 1) Overheating: The engine temperature gauge climbs into the red zone, especially under load. 2) Slow Warm-Up: The engine takes an unusually long time to reach normal operating temperature. 3) Temperature Fluctuation: The gauge bounces erratically. 4) Coolant Leaks: Leaks from the thermostat housing area. If you experience any of these issues, it is recommended to test and replace the thermostat.