Many modern vehicles (particularly light diesels) are so fuel-efficient that they won't warm up no matter how long you leave them idling. I needed to fit an ol

Many modern vehicles (particularly light diesels) are so fuel-efficient that they won't warm up no matter how long you leave them idling. I needed to fit an old-fashioned radiator blind to the Mercedes van I used at work, because in the winter the engine would not reach operating temperature in a 15-mile drive from my house to my workshop.