Besides preventing the build-up of nasty engine sludge and premature wear, protection against cold starts is one of the main reasons why you should never skip an oil change in your gasoline or diesel ...

Heavy-duty pickups and long-haul trucks rely on torquey diesel engines that are more economical, reliable, durable, and have a more straightforward construction than a comparable unleaded gas engine.

A raw, unedited cold start of the classic D4-7U. We test how this vintage diesel handles a cold start without any starting aids and reveal what it takes to get it running smoothly. Special report: ...