For all to benefit, here's what's currently in the bestlinks for spark plugs:I just pulled the plugs out of 107k mile 2002 540iA sport. They are Bosch and say BMW on them. I believe them to be original based on condition and label.
I've read a lot of the thread on here from Bluebee's links and searches which say the NGK are original. Did they change at some point during the model run?
Edit - re-read one of Bluebee's links and found the answer.
I missed that tab in all my other reading.
They're both OE.
Pay attention to this! Do not play around with substituting 1 or 2 pronged for 4 pronged! I got a full service from a non BMW garage 8 months ago. After I got the car back the motor had these flat spots and I had to be very sensitive on the gas. Soon after, I lost one cylinder and took it back to the garage. The guy told me it was the ignition coils and I replaced all 4 for 500 bucks.
The other day, after months of frustration and temporarily losing a cylinder again, I took the car to the BMW service place. They told me that there were 1 pronged plugs installed rather than the 4 pronged. 270 bucks later the car runs SOOO sweetly that I can't even describe it to you. Do not mess around with components on these cars. They are precision instruments. It might seem like your car is running fine, depending on the model but I wouldn't be surprised if there was some effect on gas consumption.
Is this another reason to go with the NGKs instead of Bosch?... the commercially-available (aftermarket) Bosch spark plugs ARE NOT the same as the original BMW Bosch plugs even though they cross-reference and they do work.
Is this the backing-out-over-time issue?Dealership technicians report problems with the commercially-available Bosch Platinum +4 spark plugs in BMW engines.
I'm sure the cutoff date between 'older' and newer is inherent in the chart above - but - if anyone knows it offhand, it would be nice to list the year where the changeover matters.when we're talking about older BMWs... there is absolutely no difference between the original BMW spark plugs and commercially-available Bosch cooper or silver plugs