Water Temperature Sensor Installation Guide

AiM Water Temperature Sensor Installation Guide

This guide covers selecting, installing, connecting and checking a compatible AiM coolant-temperature sensor for a water-cooled kart engine. Match the instructions to the exact MyChron, engine, sensor and adaptor. MyChron 5 is obsolete and no longer sold by Harris Race Radios; parts, sensors, repairs and existing-owner support continue. MyChron 6 models are the current new-unit range.

What the water temperature sensor does

It measures coolant temperature at its installation point. It does not establish a safe engine limit or prevent overheating by itself. For graph interpretation and investigation of readings, use the separate Water Temperature Sensor Guide.

What you need

  • The exact AiM sensor specified for the intended measurement and supported MyChron input.
  • A compatible adaptor if required by the engine installation, matching the hose internal diameter, sensor thread and sealing arrangement. Do not assume one 10 mm or 12 mm adaptor or a particular spanner size suits every system.
  • The correct connector and extension or patch lead for the sensor and MyChron generation.
  • Engine-approved coolant, suitable clamps and the tools specified by the engine/adaptor manufacturer.
  • The exact engine, sensor and MyChron wiring and installation instructions.

1. Choose the correct mounting location

Use the sensor location specified by the engine manufacturer or engine builder. Do not assume that the hose closest to the cylinder head is always the approved position. Confirm that the engine is water-cooled and that the sensing point measures the intended coolant flow.

2. Install the hose adaptor, where required

  1. Let the engine and cooling system cool. Follow the engine's safe draining and service procedure; never open a hot pressurised system.
  2. Fit the correctly sized adaptor at the specified location without straining or kinking hoses.
  3. Secure the hoses with the specified clamps and tightening procedure.
  4. Check the assembly is supported and clear of moving parts.

3. Install and connect the sensor

  1. Confirm thread and sealing compatibility. Use only the sealing method and tightening procedure specified for that sensor/adaptor.
  2. Route the lead away from exhaust heat, abrasion, ignition interference and steering or drivetrain movement.
  3. Identify the exact temperature input and patch lead from the MyChron wiring diagram. Do not rely on a generic “CHT/WT” port name across generations.
  4. Connect without forcing mismatched plugs. Ensure thermocouple and thermoresistor connections match the actual sensor and harness.

4. Configure the channel and alarm

Use the model-specific configuration procedure to check sensor function, channel label and Celsius or Fahrenheit units. AiM's MyChron6 manual provides automatic and manual temperature-function selection; confirm the displayed function matches the installed sensor rather than relying on an initial label alone.

Set warning and stop thresholds using the engine manufacturer's or engine builder's limits for the exact engine and class. No universal brand-wide coolant-temperature table applies, and a sensor measurement range is not an engine safety limit.

5. Fill and bleed the cooling system

Follow the exact engine manufacturer's filling and bleeding procedure. Do not assume that tilting the kart or running with the radiator cap removed is appropriate for every cooling system. Check for leaks when safe before proceeding to a controlled operational test.

6. First operational check

  • Before starting, check a plausible reading for the actual conditions and verify the correct channel function and units.
  • During a controlled warm-up, monitor the reading against the engine's specified procedure and limits.
  • Check the sensor/adaptor assembly for leaks without touching hot or moving components.
  • Confirm warning settings and save the relevant configuration before competition use.
  • Stop if there is a leak, suspected overheating or an unexplained reading. Do not rely on a smooth trace alone as proof of a correct installation.

7. Installation troubleshooting

  • Missing or implausible reading: check sensor type, channel function, units, connector and cable against the exact documentation. A reading at zero is not a universal diagnostic code.
  • Erratic values: inspect for damaged wiring, loose connections and interference; do not assume one cause.
  • Leaking adaptor: stop, cool the system and investigate the correct fit and sealing arrangement. Do not simply tighten harder.
  • Abnormal temperature: stop safely and consult the engine builder; use the interpretation guide for possible measurement and engine checks.

See also:

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