I own a 14 year old Ford Galaxy 1.9 TDI with 170,000 miles on the clock. The car has run well, until recently. The glow plug/engine management light has started coming on and now flashes on and off.

Diesel engines run on fuel that’s much thicker than gas, adding to the difficulty of cold-weather starts. To aid combustion, small electric heaters called glow plugs warm pre-combustion or combustion ...