The long warmup is a result of the greater efficiency of the diesel engine. Diesels put out much less waste heat in the ehaust and to the coolant. In fact, long idling sessions can cause excessive wear because the engine temp in many diesels will not stay in the optimum range of operation if slow idled for an extended period.
Some manufacturers offer a 'high idle' selection for extended idling. I don't know if Mercedes offer this in their consumer diesels, but they did offer it as an option in their commercial passenger vans sold in the US as the Dodge Sprinter.
It could be that the cold engine wear problem was much more of a problem with the prior generation of motor oils, and is much less of a problem using full synthetic 0W-30 or 0W-40.
Last edited by Jim314; Mar 7th, 2011 at 14:37.
|