Genuine Volvo 245 Coolant Temperature Sensors

Volvo 245 Coolant Temperature Sensors Parts and Q&A

• Temperature Sending Unit
  460191
  Q: What are the functions and testing procedures of coolant temperature sensors on Volvo 245?

  A:

  The sensor for the coolant temperature gauge is a semi-conductor device whose electrical resistance varies with temperature, supplied with a constant voltage via the temperature indicator on the instrument panel. Variations in resistance cause a varying current to pass through the sensor, which is registered on the indicator as a change in temperature. It is located on the left-hand side of the cylinder head beside the rear inlet port. To remove it, partially drain the cooling system through the tap in the cylinder block until the level has fallen just below the cylinder head, checking by unscrewing the sensor slightly to see if coolant leaks out. Once enough coolant has been drained, the sensor can be unscrewed and removed for checking. To test the sensor, attach temporary extension leads to the device and suspend it in a container of water, heating the water to boiling point. The needle on the indicator should rise smoothly as the water temperature increases, finishing between normal and hot when the water starts to boil, keeping in mind that the boiling point of water in free air is somewhat lower than that in a sealed system.