I recently replaced my 2011 Ram 2500 with a 2016 3500. Both were Cummins. The 2011 said to never idle more than 5 minutes. The 2016 book says not to idle excessively but doesn't give any indication of how long is considered excessive. We have temps here that can be well below zero and the truck has a remote starter. I'd like to start remotely and let it warm up a bit before driving. Any ideas on how long is too long to idle?