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41-6539 Water Temperature Sensor for Thermo King
41-6539 Water Temperature Sensor for Thermo King monitors engine coolant temperature and sends temperature information to the refrigeration unit control system. It is an aftermarket replacement sensor for selected Thermo King transport refrigeration units.
Product Description
The 41-6539 Water Temperature Sensor is a replacement engine water temperature sensor for selected Thermo King transport refrigeration equipment.
The sensor monitors engine coolant temperature and provides a temperature signal to the control system. Accurate coolant temperature information helps the refrigeration unit monitor engine operating conditions and respond to abnormal temperature conditions.
Thermo King parts documentation identifies 41-6539 as Sensor Ass’y Engine Water (Nickel Term.). This helps distinguish it from other Thermo King engine water temperature sensors, including 41-6538.
The 41-6539 sensor appears across a wide range of Thermo King equipment. Applications include selected MD, KD, RD, TD, TS, SB and SL series units. Some aftermarket catalogs also associate the sensor with Thermo King/Yanmar 374, 395, 482 and 486 engines.
Always check the original part number, engine model, unit model, connector and sensor specifications before ordering.
Product Specifications
| Item | Details |
|---|---|
| Product Type | Water Temperature Sensor |
| Part Number | 41-6539 |
| Alternative Number | 416539 |
| Thermo King Description | Sensor Ass’y Engine Water |
| Terminal Type | Nickel Terminal |
| Brand | Thermo King |
| Application | Transport Refrigeration Units |
| Function | Engine Coolant Temperature Monitoring |
| Engine Applications | 374, 395, 482, 486 |
| Main Unit Series | MD, KD, RD, TD, TS, SB, SL |
| Replacement Type | Aftermarket Replacement |
The terminal type and application information should be confirmed against the actual product before final installation.
Product Application
The 41-6539 water temperature sensor is listed for various Thermo King transport refrigeration applications.
| Thermo King Series | Common Models / Applications |
|---|---|
| MD Series | MD-100, MD-200, MD-300 |
| KD Series | KD-II |
| RD Series | RD-II, RD-II SR |
| TD Series | TD-II / Super TD-II |
| TS Series | TS-200, TS-300, TS-500, TS-600 |
| SB Series | SB-100, SB-110, SB-190, SB-200, SB-210, SB-230, SB-310, SB-400 |
| SB Series | SB-III and selected multi-temperature applications |
| SL Series | SL-100, SL-200, SL-300, SL-400 |
| SL Series | SL-100e, SL-200e, SL-400e, Spectrum SL |
Thermo King application catalogs also list 41-6539 for selected URD-III, UTS, Spectrum and Super-II applications. Exact compatibility can vary by engine and unit configuration.
Engine Applications
Aftermarket parts catalogs commonly associate 41-6539 with the following Thermo King/Yanmar engines:
| Engine | Related Engine Number |
|---|---|
| Thermo King 374 | 3.74 / TK374 |
| Thermo King 395 | 3.95 / TK395 |
| Thermo King 482 | 4.82 / TK482 |
| Thermo King 486 | 4.86 / TK486 |
Some sources further identify these engines with Yanmar engine families such as 3TNE72, 4TNE84 and 4TNE88. Confirm the engine identification before ordering.
Main Function
The engine water temperature sensor provides important temperature information for the refrigeration unit.
It helps the system:
- Monitor engine coolant temperature.
- Send temperature data to the control system.
- Detect abnormal engine temperature conditions.
- Support proper engine operation.
- Assist technicians with refrigeration unit diagnosis.
A reliable temperature signal helps the controller monitor engine operating conditions during refrigeration operation.
Common Replacement Symptoms
A damaged or aging water temperature sensor may cause:
- Incorrect coolant temperature readings.
- Unstable temperature signals.
- Temperature-related warning messages.
- Abnormal engine monitoring.
- Intermittent sensor signals.
- Difficulty diagnosing cooling system problems.
These symptoms can also come from damaged wiring, poor electrical connections, or other components. Technicians should check the complete sensor circuit before replacement.
Related and Cross-Reference Part Numbers
Several older Thermo King numbers are associated with the 41-6539 replacement application.
| Part Number | Reference |
|---|---|
| 41-6539 | Main part number |
| 416539 | Alternative number format |
| 41-2330 | Related / older reference |
| 41-5066 | Related / older reference |
| 41-5067 | Related / older reference |
| 41-3977 | Related / older reference |
| 41-1314 | Related / older reference |
| 1E27507G02 | Related reference |
| 1E08302G03 | Related reference |
These numbers appear together in aftermarket catalogs, but customers should confirm the application before treating them as interchangeable.
41-6539 vs. 41-6538
Both 41-6539 and 41-6538 are Thermo King engine water temperature sensors, but they cover different application groups.
| Part Number | Description | Typical Application |
|---|---|---|
| 41-6539 | Engine Water Temperature Sensor | MD, KD, RD, TD, TS, SB, SL and related units |
| 41-6538 | Engine Water Temperature Sensor | Selected T-Series, SLX, SLXe, SLXi and related units |
Thermo King parts documentation specifically distinguishes 41-6539 as the nickel-terminal engine water sensor. Therefore, customers should not choose between 41-6539 and 41-6538 based only on the product name.
Why Choose a 41-6539 Replacement Sensor?
- Designed for selected Thermo King refrigeration applications.
- Monitors engine coolant temperature.
- Supports reliable temperature monitoring.
- Suitable for aftermarket repair and maintenance.
- Covers a broad range of Thermo King refrigeration equipment.
- Useful for Thermo King parts distributors and refrigeration repair companies.
Suitable Customers
This product is suitable for:
- Thermo King parts distributors
- Refrigeration parts wholesalers
- Transport refrigeration repair shops
- Truck refrigeration service companies
- Trailer refrigeration maintenance companies
- Fleet maintenance departments
- Thermo King aftermarket parts suppliers
Ordering Information
Before ordering the 41-6539 Water Temperature Sensor, customers should contact us to provide:
- Original part number.
- Thermo King unit model.
- Engine model.
- Unit serial number, if available.
- Existing sensor photo when necessary.
- Connector and terminal information.
This information helps confirm the correct sensor because Thermo King uses several water temperature sensor part numbers across different equipment generations.
