There is discussion on other diesel forums about this topic. Some don't like the theory of excessive wear and tear on the engine (on start up) in regards to shutting down often for short periods of time and then re starting. Some believe that there is a small moment of time or travel while the piston travels without little or no lubrication b/t the rings of engine. This over time adds wear and reduces the life of a engine. For me, the Dodge A/c has trouble keeping up with the 115 degree summer AZ months and I have it locked and running with my removable key fob.