Quote:
Originally Posted by Dackelone
Opinion is split on this. Read my Spark plug DIY... it was discussed somewhat on the last page(3). I have read many posts where people went with aftermarket Bosch plugs and had no problems. But then again I have read four or so posts and seen where people had a misfire issue do to (bad) spark plugs.
I decided to play it safe and just buy my sparkplugs at my local dealer.  |
FWIW, from Mike Miller's Old School Maintenance Guide:
Original BMW Bosch Spark Plugs vs. Aftermarket Bosch Spark Plugs
Like just about everything else on the modern BMWs, Bosch spark plug choice is complicated and confusing. The short answer is if you order the spark plugs from BMW (sometimes there is a choice between Bosch or NGK), then you are good to go and there is no confusion. But they are expensive.
Savvy enthusiasts have found that Bosch has a part number for commercially-available spark plugs that cross-references to the BMW original equipment Bosch spark plugs, often at a fraction of the price. The problem is, the commercially-available (aftermarket) Bosch spark plugs are not always the same as the original BMW Bosch plugs even though they cross-reference and they do work.
Dealership technicians report problems with the commercially-available Bosch Platinum +4 spark plugs in BMW engines. I have never seen this personally, but physical inspection does reveal differences in insulator design between the original BMW Bosch spark plugs for the modern cars and the commercially-available Bosch Platinum +4.
We’re talking about the newer multiple-coil BMWs above. Now, when we're talking about older BMWs with a single ignition coil, where the original BMW specified spark plugs are Bosch copper or silver plugs, everything is completely different. On those cars, there is absolutely no difference between the original BMW spark plugs and commercially-available Bosch copper or silver plugs. I realize this requires a certain intimate knowledge of Bosch spark plugs, and I don’t know what to tell you about that except to ask if you don’t know, or just buy them from the dealer.