Yanmar 4TNV98 Thermostat 121850-49800 – Engine Cooling System Part for Industrial & Agricultural Machinery

Product Details

Product Overview

This high-quality thermostat, part number 121850-49800, is a direct replacement for Yanmar 4TNV98 series diesel engines. Designed to regulate engine operating temperature for optimal performance and fuel efficiency, this component is essential for maintaining the longevity of your equipment. We ship globally, serving major industrial markets across North America, Europe, Asia-Pacific, and the Middle East, ensuring fast delivery to ports and industrial centers worldwide.

Key Features & Benefits

• Precise Temperature Control: Ensures the engine reaches and maintains its ideal operating temperature quickly, reducing wear and improving combustion efficiency.
• Durable Construction: Manufactured from high-grade, corrosion-resistant materials to withstand extreme thermal cycles and harsh operating environments.
• Direct Fitment: Designed as a genuine OEM replacement, guaranteeing a perfect seal and seamless integration with the 4TNV98 cooling system without modifications.
• Enhanced Fuel Economy: Proper thermostat function prevents engine from running too cool, which directly contributes to lower fuel consumption and reduced emissions.
• Reliable Performance: Rigorously tested for opening and closing temperature accuracy, ensuring consistent performance under load and in varying ambient conditions.

Technical Specifications

OEM Cross-Reference

This thermostat replaces the following original Yanmar part numbers. Please verify your current part number for exact fitment.

• 121850-49800 (Primary OEM)
• 119650-49800 (Superseded/Alternate OEM)
• 119650-49810 (Superseded/Alternate OEM)

Compatibility

This thermostat is specifically designed for the Yanmar 4TNV98 series industrial diesel engines. Common applications include:

• Engine Models: 4TNV98, 4TNV98T (Turbo), 4TNV98-Z
• Agricultural Tractors: Yanmar YT series, various compact tractor models.
• Construction Equipment: Mini excavators, compact track loaders, and skid steer loaders (e.g., Yanmar Vio series, John Deere compact models using Yanmar engines).
• Industrial Machinery: Forklifts, generators, pumps, and welders powered by the 4TNV98 engine.

Note: Always confirm your engine serial number and housing design, as minor variations may exist between naturally aspirated and turbocharged versions.

Global Supply & Distribution

We are a dedicated supplier of Yanmar engine components with a robust global logistics network. Our capabilities ensure your operations stay running:

• Worldwide Shipping: Reliable delivery via DHL, FedEx, UPS, TNT, and sea freight to major ports.
• Major Markets Served: North America (USA, Canada, Mexico), Europe (Germany, UK, Netherlands), Asia-Pacific (Japan, Korea, Australia), Middle East (UAE, Saudi Arabia), and Africa (South Africa, Nigeria).
• Fast Delivery: Orders placed before 3 PM (EST) ship same day. Express shipping to major industrial hubs in 3-7 business days.
• Export Expertise: Experienced in international trade documentation, customs clearance, and compliance with global standards.

Quality Assurance

We prioritize quality and reliability to ensure your equipment performs at its peak.

• Manufacturing Standard: Produced in ISO 9001:2015 certified facilities, ensuring consistent quality control.
• Testing: Each batch is tested for precise opening temperature (82°C ± 2°C) and full lift performance to meet OEM specifications.
• Warranty: 12-month warranty against manufacturing defects. We stand behind our parts.

FAQ

Q: How do I know if this thermostat fits my 4TNV98 engine?
A: Check the part number stamped on your current thermostat housing. If it is 121850-49800, 119650-49800, or 119650-49810, this unit is a direct replacement. Also verify your engine is a 4TNV98 series (not a 4TNV84 or 4TNV106). The thermostat housing gasket is typically sold separately; we recommend replacing the gasket during installation.

Q: What is the correct installation procedure for this thermostat?
A: 1) Drain coolant to below the thermostat level. 2) Remove the thermostat housing bolts (usually 2-3 bolts). 3) Note the orientation of the old thermostat (jiggle pin/air bleed valve should be at the highest point). 4) Clean the mating surfaces thoroughly. 5) Install the new thermostat with a new gasket. 6) Torque housing bolts to manufacturer specifications (typically 8-12 Nm). 7) Refill coolant and bleed air from the system. Run engine to check for leaks and proper temperature regulation.

Q: What are the signs of a failing thermostat on a 4TNV98 engine?
A: Common symptoms include: 1) Engine overheating or running too cool (below 70°C). 2) Fluctuating temperature gauge. 3) Heater blowing cold air (in cabbed vehicles). 4) Coolant leaking from the thermostat housing. 5) Poor fuel economy. If you experience any of these, test the thermostat by placing it in hot water (82°C) to see if it opens. If it remains closed or opens too early, replace it immediately.