LEMON Manuals: Even more car manuals for everyone
Home >> BMW >> 2021 >> 840i 2D Convertible >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Engine Electrical System -- Repair (G14, G15, & G16) >> 12 12 Spark Plugs >> 12 12 011 Removing and installing/replacing all spark plugs (M850i xDrive coupe/convertible/Gran Coupe sedan) >> Replacing all spark plugs

Replacing all spark plugs

WARNING: Hot surfaces. 
Risk of burning! 
  • Perform all work only on components that have cooled down.
WARNING: Hot fluids. 
Risk of scalding! 
  • Conduct all work in the vehicle wearing appropriate personal protective equipment only.
CAUTION: Materials harmful to health. 
Contact with fluids harmful to health! 
  • Note and follow safety instructions on containers.
  • Conduct all work in appropriate personal protective equipment only.
NOTE: TECHNICAL INFORMATION 
Immobilization period-long fill of coolant! 
Do not reuse used coolant.
When replacing and removing components which rely on the corrosion protection effect of the coolant, it is essential to change the coolant. The cooling system must therefore be emptied and refilled.
In the case of other removal work involving the draining of part quantities of coolant, the coolant level must be topped up with new coolant.
NOTE: TECHNICAL INFORMATION 
Notes on work at the cooling system form the basis of these repair instructions and must be complied with at all times.
For additional information see: NOTES FOR WORKING ON THE COOLING SYSTEM .
NOTE: TECHNICAL INFORMATION 
Collect and dispose of emerging fluids. Observe country-specific waste disposal regulations.

Preliminary work 

Removing the spark plug of cylinder bank 1 

WARNING: Hot surfaces. 
Risk of burning! 
  • Perform all work only on components that have cooled down.
CAUTION: Swirling dirt particles caused by compressed air. 
Injury hazard! 
  • Collect dirt particles, e.g. when blowing out, use cloth to do so.
  • Wear safety goggles.
NOTE: TECHNICAL INFORMATION 
Clean spark plug slot with compressed air. 
The spark plug shaft must be cleaned using compressed air after having removed the ignition coils and before removing the spark plugs. After having removed the spark plugs, once again check the sealing surface for contamination and (if necessary) clean using a moist cloth or clean using compressed air.
Deposits that are not removed according to instructions may enter the combustion chamber and lead to uncontrolled combustion. Remaining deposits on the spark plug sealing surfaces may lead to leaks and the spark plugs may come loose during engine operation.
Spark plug threads must not be greased or oiled. Insufficiently tightened spark plugs may cause leaks and the sparks plugs may come loose during engine operation.
NOTE: The description is provided only at one component. The procedure is the same for all other components.
G14261772Courtesy of BMW OF NORTH AMERICA, INC.

Removing spark plug of cylinder bank 2 

WARNING: Hot surfaces. 
Risk of burning! 
  • Perform all work only on components that have cooled down.
CAUTION: Swirling dirt particles caused by compressed air. 
Injury hazard! 
  • Collect dirt particles, e.g. when blowing out, use cloth to do so.
  • Wear safety goggles.
NOTE: TECHNICAL INFORMATION 
Clean spark plug slot with compressed air. 
The spark plug shaft must be cleaned using compressed air after having removed the ignition coils and before removing the spark plugs. After having removed the spark plugs, once again check the sealing surface for contamination and (if necessary) clean using a moist cloth or clean using compressed air.
Deposits that are not removed according to instructions may enter the combustion chamber and lead to uncontrolled combustion. Remaining deposits on the spark plug sealing surfaces may lead to leaks and the spark plugs may come loose during engine operation.
Spark plug threads must not be greased or oiled. Insufficiently tightened spark plugs may cause leaks and the sparks plugs may come loose during engine operation.
NOTE: The description is provided only at one component. The procedure is the same for all other components.
G14261774Courtesy of BMW OF NORTH AMERICA, INC.

Installing spark plug of cylinder bank 2 

NOTE: The description is provided only at one component. The procedure is the same for all other components.
G14261774Courtesy of BMW OF NORTH AMERICA, INC.

Installing the spark plug of cylinder bank 1 

NOTE: The description is provided only at one component. The procedure is the same for all other components.
G14261772Courtesy of BMW OF NORTH AMERICA, INC.

Follow-up work