A tapping/rattling noise may be noticed from the valve train area. This condition usually occurs after the engine has been turned off at normal operating temperature and then not warmed up to full operating temperature during the next series of cold starts. This operating condition can occur, for example, on new vehicles which have been delivered to Mazda dealers (due to loading and unloading from transport trucks or customers moving their vehicles in and out of their garages to wash the vehicle, etc.)