BMW Cars 1999-06

Removal & Installation

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The thermostat is located near the water pump, either on the cylinder head or intake manifold on some vehicles and is located between 2 coolant hose sections on some vehicles.

Always drain some coolant out and save it in a clean container before removing the thermostat.

To remove and install thermostat, refer to water pump.

E30 Models



M20 Engine
  1. Partially drain the coolant. Save the coolant in sealed containers if being reused or dispose of safely.
  2.  
  3. Remove the 3 bolts on the thermostat housing located at the intake side of the engine.
  4.  
  5. Pull the thermostat housing off and remove the thermostat. Note the positioning of the thermostat.
  6.  

To install:

  1. Replace the thermostat with a the support bar facing out. Replace the O-ring.
  2.  
  3. Install the thermostat housing and torque the bolts to 6-7 ft. lbs. (8-10 Nm).
  4.  
  5. Fill the cooling system with coolant mixture and bleed.
  6.  

M42 Engine
  1. Partially drain the coolant. Save the coolant in sealed containers if being reused or dispose of safely.
  2.  
  3. Remove the 4 bolts on the thermostat housing located at the front of the cylinder head. It may be necessary to remove the hoses from the housing first if the housing can't be pulled forward enough.
  4.  
  5. Pull the thermostat housing off and remove the thermostat. Note the positioning of the thermostat.
  6.  

To install:

  1. Replace the thermostat with a the support bar facing out. Replace the O-ring and gasket.
  2.  
  3. Install the thermostat housing and torque the bolts to 71-88.5 inch lbs. (8-10 Nm).
  4.  
  5. Fill the cooling system with coolant mixture and bleed.
  6.  

S14 Engine
  1. Drain the coolant. Save the coolant in sealed containers if being reused or dispose of safely.
  2.  
  3. Loosen the hose clamps holding the thermostat at the exhaust side of the engine. Place a drain pan under the thermostat to catch the coolant that will drain out.
  4.  
  5. Remove the thermostat.
  6.  
  7. Install the thermostat using new clamps. Fill the cooling system and bleed.
  8.  

E36 Models



The thermostat is located inside the black composite housing on the front of the cylinder head.

  1. Note the radio security code and disconnect the negative battery cable.
  2.  
  3. If installed, remove the top trim cover from the radiator.
  4.  
  5. On models with a belt driven cooling fan, remove the cooling fan. For details refer to engine fan removal in this section.
  6.  
  7. Drain the engine coolant into a sealable container.
  8.  
  9. Loosen the radiator hose clamps and remove the radiator hoses.
  10.  


NOTE
The hoses have a tendency to bake onto the composite housing material. If necessary use a suitable lubricating spray and a blunt right angle hook or cotter key removal tool to relieve the hose from the fitting.

  1. Using a 10mm socket, short extension and ratchet, loosen the housing mounting bolts and remove the housing.
  2.  
  3. If the thermostat is installed into the housing it should be replaced as a unit with the housing. It is possible to remove the thermostat from the housing, however as an original equipment replacement part it is only available as part of the housing. For documentation purposes only, the thermostat was removed from the housing by pressing down on the thermostat and turning the end of the thermostat counterclockwise to release the metal tabs from the retaining brackets.
  4.  



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Fig. The thermostat housing is on the front of the cylinder head-M44 engine shown



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Fig. This thermostat is installed into the housing and is replaced with the housing-M44 engine shown



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Fig. For documentation purposes only, this thermostat was removed by pressing down and turning the end counterclockwise. The metal tabs seat in the housing bracket-M44 model shown



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Fig. Carefully remove the seal and . . .



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Fig. . . . replace with a new seal during reassembly-M44 model shown



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Fig. Apply an anti-seizing compound to the housing bolts



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Fig. When you install the thermostat, make sure the bleed hole is facing up as shown

To install:

  1. Inspect the housing for cracks, especially around the bolt holes. Some early model housings do not have metal sleeves in the bolt holes and have a tendency to crack if over-tightened.
  2.  
  3. Replace the thermostat housing seal. On 6-cylinder engines, replace the thermostat seal.
  4.  
  5. Install the thermostat making sure the air bleed hole is facing UP .
  6.  


WARNING
The thermostat must be installed with the vent hole facing up. Failure to install the thermostat properly could result in overheating and possible engine damage.

  1. Coat the thermostat housing bolts with a suitable anti-seizing compound and tighten in a crisscross pattern to the specification given below. DO NOT overtighten the housing bolts.
    1. Thermostat housing fastener tightening specifications:

      M6: 88.5 inch lbs. (10 Nm)
       
      M7: 11 ft. lbs. (15 Nm)
       
      M8: 11 ft. lbs. (15 Nm)
       

    2.  

  2.  
  3. The balance of the assembly is in reverse order of disassembly making sure to use the correct mixture of coolant, properly bleed the cooling system and enter the radio security code.
  4.  

 
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