New redesigned coils for BMWs from Bosch, [part numbers 0 221 504 464/00124 and 0 221 504 407/00044] have had a number of automotive service technicians wondering what happened to the “snap.”
Some technicians in the field believe that the coil was held in place by a connection between the contact bolt of the spark plug and contact inside the coil, and this “snap” sound must always be heard to indicate proper installation. In reality, the coil is held in two places: by the rubber boot that slips over the ceramic part of the spark plug, and by the sealing lips at the upper end of the coil.
In other words, the original design actually gripped the spark plug tip and felt more secure whereas the new design uses a contact spring on the spark plug tip. This design may not feel like the connector is gripping the spark plug, but in reality, it does the job just as well, if not better than the old design.
Aesthetically, the change of the collar/housing around the coil body from a metallic to a plastic housing, and the spark plug connector, are obvious improvements for the appearance of this coil body and provides improvement in fit, form, and function as intended by BMW. Bosch and BMW have also used this newer connector design in hundreds of thousands of OE (original equipment) BMW coils in recent years with no performance problems or other issues.
For information on the entire portfolio of Bosch products for the aftermarket, visit http://www.boschautoparts.com.
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