The BMW E36 M3 produced between 1992 and 1999 had two different six cylinder engines fitted during its lifetime:
- a 3.0L version S50 B30 (1992–1995)
- a 3.2L version S50 B32 (1995–1999)
OEM (original equipment manufacturer) Spark plugs used by BMW in these engines were of two different types:
- NGK PKR7A plugs fitted in the S50 B30
- Bosch FGR8KQE plugs in the S50 B32
Original BMW part number for spark plugs: 12129069048
Upgrading to Iridium spark plugs
Some M3 owners, especially those who race or use their M3 on the track frequently have upgraded from the original spark plugs to Iridium plugs, with the NGK IX Iridium BKR6EIX being particularly popular among performance enthusiasts.
The main advantages in using Iridium plugs are that they last longer than normal copper or platinum coated plugs. They also have a finer tip which allows a hotter spark to be produced using the same current, which provides increased conductivity and improved anti-fouling of the plugs, leading to better fuel efficiency and better overall performance.
Changing spark plugs on a BMW E36 M3
The BMW M3 service manual recommends plug changes every 30,000 miles or 24 months as part of the Inspection II maintenance program.
How to replace the spark plugs on your BMW E36 M3:
- First, remove the 2 round caps on the engine cover to access the 2 X 10mm nuts holding it in place
- Remove the 2 X 10mm nuts and unscrew the oil filler cap in order to take the trim cover off
- Put the oil filler cap back on – to avoid any contamination of the oil
- Remove each ignition coil by prising up the flat metal clip and removing the two bolts which hold each electrical lead in place
- Each coil is specific to each cylinder, so make sure you reinstall them as they were originally
- Remove each plug with a spark plug wrench or socket wrench – check each plug for wear or abnormal residue
- Before inserting the new plugs you can apply some anti-seizing compound on the thread