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

Thermostat

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REMOVAL & INSTALLATION 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 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.  

M30 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 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 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 the support bar facing out. Replace the O-ring and gasket.
  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.  

M50 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 the support bar facing out and the vent hole or arrow facing up. Replace the O-ring and gasket.
  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.  

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.  

S38 Engine

  1. Partially drain the coolant. Save the coolant in sealed containers if being reused or dispose of safely.
  2.  
  3. Disconnect the hoses from the thermostat housing located on the exhaust side of the engine.
  4.  
  5. Remove the 5 screws holding the thermostat housing.
  6.  
  7. Pull the thermostat housing off and remove the thermostat. Note the positioning of the thermostat.
  8.  

To install:
  1. Replace the thermostat with the support bar facing the engine and the vent hole or arrow facing up. Replace the seal on the coolant passage.
  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.  

 
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