BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engine
- 4. Cooling system
   4.2. Specifications
   4.3. Antifreeze
   4.4. Thermostat
   4.5. Radiator
   4.6. Fans and coupling of the drive
   4.7. Pump of cooling liquid
   4.8. Sensor of temperature of cooling liquid
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
+ 14. Useful tips


4.8. Sensor of temperature of cooling liquid


The sensor of temperature of cooling liquid (violet-brown wire) on the 4-cylinder engine

The sensor of temperature of cooling liquid (violet-brown wire) on the 6-cylinder engine

The sensor (or the index) are checked by check of their resistance and connection with weight (if this connection is provided by the electric circuit, see subsection 13.2.4).

To establish malfunction of the sensor, index or conducting it is possible on the basis of the following simple checks. If the arrow of the index of temperature is near an initial mark of a scale in the heated-up engine, then disconnect the socket from the sensor and at the included ignition connect a crossing point a socket conclusion to weight. If at the same time the arrow of the index moved to an extreme part of a scale, then replace the sensor. Otherwise either conducting or the index are faulty. If indications of temperature are obviously overestimated on the cold engine, and at a socket detachment from the sensor of the shooter comes back to initial situation, then the sensor is faulty. If the provision of an arrow does not change, then in a wire or in the index there is a short circuit on weight.

On the M40 engine the sensor of temperature is screwed in the left part of a head of cylinders. On other engines the sensor as a rule is screwed in the thermostat case. On a part of cars 2 sensors are provided, only one of which works with the index.

When replacing the sensor some loss of liquid is possible. Wrap the new sensor on sealant.