Changing spark plugs on BMW E46 325i

Tools :

1 Torx key 30 for the filter holder screws.

1 Slotted screwdriver.

1 10mm socket for the upper engine cover screws as well as the coil retaining screws.

1 x 16mm spark plug wrench.

1 Torque or angle wrench.

Consumables:

Penetrating oil and copper oil or grease (optional)

Pull the lever to unlock the engine hood and also the second lever at the radiator grille.

Pull the lever to completely unlock the hood then raise it as far as it will go.

Locate the cabin filter compartment.

The intervention takes place at the engine level. It is therefore necessary to ensure that the latter is sufficiently cold to avoid any burns.

Perform a quarter turn counterclockwise on the 3 screws holding the cabin filter cover to unlock them.

Remove the cover by first pulling upwards (A) then forwards (B).

Proceed to remove the cabin filter.

You can take advantage of this intervention to replace your cabin filter if it is clogged.

Open the electrical harness chute by unclipping the 4 clips.

Remove the 4 TORX T30 screws from the filter support.

Gently pull the electrical cable and the corrugated sheath out of the duct.

Remove the filter holder by pulling upwards (A) then forwards (B).

You should get this result after removing the cabin filter bracket.

Using a slotted screwdriver, remove the 4 screw covers on the engine cover.

Using a 10mm socket, remove the 4 engine cover screws.

Remove the engine oil filler cap.

Remove the engine cover by pulling upwards.

It is important to be careful when removing the oil filler cap so as not to allow anything to enter the engine.

Immediately replace the engine oil filler cap.

Identify and/or number the 6 reels if necessary.

Using a slotted screwdriver, remove the electrical connector from the coil by pulling the metal tab upwards (A). Then release the connector (B).

Repeat this operation on the other coils.

Remove the 2 screws (10mm socket) that hold the coil in place.

Repeat this operation on the other coils.

Remove the coils by pulling them upwards.

Note the presence of a ground wire on the coil on the far left as well as the coil on the far right.

Make sure the spark plug wells are clean. If not, clean them (compressed air, vacuum, etc.).

Using an extension and a 16mm spark plug socket, remove the spark plug, keeping the spark plug wrench straight, in line with the spark plug so as not to damage the thread.

Check the condition of the spark plug. In this case it is black and oily. The other spark plugs will have the same appearance. This indicates advanced and general wear of the engine. Normally, the spark plug should be dry and light brown in color.

Do not force when removing a spark plug to avoid it breaking in the cylinder head. If removal is difficult, proceed by loosening/tightening in succession and proceed gradually. The use of a penetrating oil can also be considered.

Compare the old spark plug then the new one.

Optional: Lightly oil the spark plug threads to make future disassembly easier. Copper grease may also work.

Using a 16mm spark plug socket and an extension, screw the spark plug into its housing by hand until contact is made.

Proceed with the final tightening of the spark plug which can be done using 2 different methods:

1) Torque: using a torque wrench, tighten the spark plug to a torque of between 25Nm and 30Nm.

If the spark plug threads have been oiled/greased then tighten to 25Nm.

2) Angular: using an angle wrench, tighten the spark plug at an angle of between 180° and 240°.

Replace the coil.

Now repeat all the operations from step 8 for the other candles.

Replace the screws holding the 6 coils and tighten them.

Don't forget the 2 ground braids.

Replace the coil connector:

(A) Pull the metal tab upwards,

(B) Install the connector,

(C) Lock the connector by pressing on it.

Repeat this same operation on the remaining 5 reels.

Remove the engine oil filler cap.

Replace the upper engine cover.

Immediately replace the engine oil filler cap.

Screw in the 4 screws (10mm socket) of the engine cover then replace the 4 small covers.

It is important to be careful when removing the oil filler cap so as not to allow anything to enter the engine.

Replace the cabin filter bracket.

Screw in the 4 screws (Torx T30) of the support.

Install the cabin filter.

Replace the cabin filter cover.

Lock the 3 bracket screws by turning them a quarter turn clockwise.

In case the chute has come off the filter support then put it back in place.

Reposition the cable and the corrugated sheath in the duct.

Close the chute by clipping the 4 locking points.

Proper engine starting will be the end of this tutorial.