So far I have been able to obtain the production date of six Z4MCs with loose or failed engine mount bolts. All were from October, November or December 2006. If you have had or discover a problem with loose or broken engine mount bolts on your Z4M, please post the production date of your car here. The month and year of production is printed on the drivers side door jamb sticker. Eventually this information may be helpful to someone like the individual who had to pay $800 to repair broken engine mount bolts when his warranty claim was refused.