BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

Sending Units and Sensors

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REMOVAL & INSTALLATION Coolant Temperature Sensor



M42 ENGINE (FOR DME)

See Figure 1

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Fig. Fig. 1: dme coolant temperature sensor engine mounted in E36 318i

The coolant temperature sensor for the dme unit is located in the cylinder head below and just behind the front engine lifting loop.

  1. Pull off the sensor connector.
  2.  
  3. Remove the crankcase breather hose from the valve cover.
  4.  
  5. Use a crowsfoot wrench on an extension and unscrew the sensor.
  6.  
  7. Install the sensor with a new crush washer and tighten to 11 ft. lbs. (15 Nm).
  8.  

M42 ENGINE (FOR GAUGE)

See Figures 2, 3, 4 and 5

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Fig. Fig. 2: Sensor locations on the M42 engine



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Fig. Fig. 3: Intake manifold support mounting bolts on M42 engine



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Fig. Fig. 4: Pull the electric wire duct forward to expose the coolant temperature sensor on the M42 engine



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Fig. Fig. 5: Make sure the rubber seals are in place on the M42 engine when replacing the wire duct

The coolant temperature sensor for the temperature gauge is located on the cylinder head further back from the dme temperature sensor. It is below the second intake port.

  1. Remove the air cleaner assembly and the crankcase breather hose.
  2.  
  3. Remove the intake manifold support and pull the wire duct forward.
  4.  
  5. Disconnect the sender and remove using a crowsfoot wrench on an extension.
  6.  

To install:
  1. Install the sensor with a new crush washer and tighten to 12.5-13.5 ft. lbs. (17-19 Nm).
  2.  
  3. Replace the lead duct and connect the electrical connector in their original positions. Be sure the rubber grommets are installed correctly to prevent water from entering the lead duct.
  4.  
  5. Install the intake manifold support and tighten to 15-17 ft. lbs. (20-24 Nm). Install the air cleaner assembly and the crankcase breather hose.
  6.  

M20 AND M30 ENGINES

The coolant temperature sensors are located on the coolant outlet on the left side of the engine. This is the junction of the coolant hoses where the coolant flows to the engine block. The dme coolant temperature sensor has a blue colored connector body. The gauge temperature sensor is typically colored brown.

  1. Pull off the sensor connector.
  2.  
  3. Use a crowsfoot wrench on an extension and unscrew the sensor.
  4.  
  5. Install the sensor with a new crush washer and tighten to 12.5-13.5 ft. lbs. (17-19 Nm).
  6.  

M50 ENGINE

On the M50 engine, the coolant temperature sensors are located under the intake manifold on the engine. The forward-most sensor is the dme sensor and the rear sensor is for the temperature gauge.

  1. Pull off the sensor connector.
  2.  
  3. Use a crowsfoot wrench on an extension and unscrew the sensor.
  4.  
  5. Install the sensor with a new crush washer and tighten to 12.5-13.5 ft. lbs. (17-19 Nm).
  6.  

S14 ENGINE

The coolant temperature sensors on the S14 engine are located in the coolant pipe above the exhaust side of the engine. The rear sensor services the dme and the forward services the temperature gauge.

  1. Pull off the sensor connector.
  2.  
  3. Use a crowsfoot wrench on an extension and unscrew the sensor.
  4.  
  5. Install the sensor with a new crush washer and tighten to 12.5-13.5 ft. lbs. (17-19 Nm).
  6.  

S38 ENGINE

See Figure 6

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Fig. Fig. 6: Temperature gauge sensor mounted on the thermostat housing on the S38 engine

The coolant temperature sensors on the S38 engine are located in the coolant pipe above the exhaust side of the engine and in the thermostat housing. The unit in the coolant pipe is the dme sensor and the unit in the thermostat housing is for the temperature gauge.

  1. Pull off the sensor connector.
  2.  
  3. Use a crowsfoot wrench on an extension and unscrew the sensor.
  4.  
  5. Install the sensor with a new crush washer and tighten to 12.5-13.5 ft. lbs. (17-19 Nm).
  6.  

Oil Pressure Switch

LOCATIONS

See Figure 7

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Fig. Fig. 7: Oil pressure switch on the M42 engine

M20 engine:

The oil pressure switch is located on the engine block near the oil filter.

M30 engine:

The oil pressure switch is located on the oil filter housing. It is on the upper side of the base.

M42 engine:

The oil pressure switch is located on the oil filter housing. It is on the back side of the base.

M50 engine:

The oil pressure switch is located on the oil filter housing. It is on the back side of the base behind the line fittings.

S14 engine:

The oil pressure switch is located on the oil filter adapter housing.

S38 engine:

The oil pressure switch is located on the oil filter housing. It is on the upper side of the base. The temperature sender for the temperature gauge is mounted sideways below the pressure switch.

REMOVAL & INSTALLATION
  1. Remove the electrical connector.
  2.  
  3. Loosen and remove the switch.
  4.  
  5. Install the sender with a new crush washer and tighten to 22-29 ft. lbs. (30-40 Nm) for the M20 and M30 engines. Tighten to 17-22 ft. lbs. (24-31 Nm) for the M42 engine. On the M50, S14 and S38 engines tighten to 12-17 ft. lbs. (17-23 Nm).
  6.  
  7. Connect the electrical lead.
  8.  

Electric Fan Switch See Figure 8

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Fig. Fig. 8: Electric fan switch and coolant level sensor on an integral expansion tank radiator

The electric fan switch is located on the radiator body. The tightening torque is 9.5-10 ft. lbs. (13-14 Nm).

Coolant Level Sensor

There is a coolant level sensor located in the coolant expansion tank. On expansion tanks mounted separate from the radiator, the sensor is mounted through the top tank. On integral radiator mounted expansion tanks it is mounted in the bottom of the expansion tank.

Oil Level Sensor

The is an oil level sensor mounted in the oil pan. It is accessible either at the top of the oil pan extension or through the bottom of the oil pan depending on the chassis and engine combination.

 
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