[jt335i]

Although the mechanic you brought it to may have worked on other BMWs, does his place specialize in BMWs and other German cars or is it a non-BMW mechanic/service center that works on various domestic and foreign cars? If that place does not specialize in BMWs, you need to take it to another independent shop that really knows how to service a 335 and have them check it.

I have a trusted mechanic who used to work at same BMW dealer where I first bought my 335. I take my car to him for all my maintenance services and repairs and my mechanic said these 335s require specialized BMW technicians who really know what they're doing and know what are the correct parts to use.