DH is a diesel mechanic. The warming up of the engine depends on the size of the engine and the temperature outside. I DOUBT it is cold enough to warrant the engine idling for longer than 2 min..... I thought California had emissions testing for all vehicles? If his exhaust is that bad I bet he is not passing the emissions testing either.
Give him the plans to convert to biodiesel......
Give him the plans to convert to biodiesel......