3E-2028 (3E2028) Caterpillar Water Temperature / Temperature Switch/Sensor is used to monitor engine coolant temperature and serves as a common wear part for classic CAT models. I. Core Specifications (OEM Standard)

Part Type: NTC Thermistor-type Temperature Switch / Sensor

Function: Monitors coolant / engine temperature; transmits signals to the ECU / instrument panel; triggers high-temperature alarms or fan control

Electrical Interface: 2-pin sealed blade connector

Mounting: Direct threaded installation (fits into engine block / coolant passages)

Material: Brass body + Thermistor core

Weight: Approx. 0.2–0.3 kg

Temperature Range: Adapted for CAT engine operating conditions (approx. **-40°C to 130°C**)

Power / Signal: 5V system; analog voltage output (0.5–4.5V)

Resistance Characteristics (Reference): 25°C ≈ 2.5kΩ; 100°C ≈ 150Ω (Tolerance: ±3%)

II. Applicable Models (Mainstream)

Excavators: 320, 325, 330, 336 Series (B/C/D/E Types)

Loaders / Scrapers: 950, 966, 980, IT Series

Motor Graders: 12H, 140H, 160H

Compactors: CS-323C, CS-423E, CP-433E

Engines: 3304, 3306, 3406, 3408, 3412, etc.

Others: 517, 527 Skidders; 777 Mining Trucks; R1300 Underground Equipment, etc.

III. Replacements and Interchangeability

OEM Replacement Part No.: CA3E2028 (Direct replacement)

Domestic Replacement Parts: Generic aftermarket replacements available; requires verification of thread specifications and resistance characteristics

Cross-Reference: Can be cross-referenced and selected as an alternative to CAT water temperature sensors such as 2W-8915, 102-0050, etc.

V. Fault Diagnosis (Quick Self-Check) Resistance Measurement (Cold Engine): At 25°C, the reading should be close to 2.5 kΩ; a significant deviation indicates a fault.

Voltage Measurement (Warm Engine): With the engine idling and coolant temperature at a normal level, the signal voltage should fall within the 1–3 V range.

Instrument Panel Anomalies: If the coolant temperature gauge remains static, false alarms are triggered, or the cooling fan runs continuously, prioritize troubleshooting this specific sensor.