Why won’t my diesel John Deere start in the cold?
Cold temps affect combustion; try using a block heater and proper cold-start technique.
Diesel engines rely on high cylinder temperatures to ignite fuel, and cold weather can significantly reduce cranking speed and combustion efficiency. When the temperature drops, the engine oil thickens, and battery performance decreases—making it harder for the engine to turn over and reach ignition temperature.
Start by plugging in a block heater 2–4 hours before use to warm the engine block and oil, making cranking easier. Make sure your battery is in top condition, as cold weather reduces voltage output. Use winter-grade diesel or add anti-gel additives to prevent fuel from waxing (gelling) in low temperatures.
Always allow the glow plugs (or intake heaters) to fully cycle before cranking the engine - typically indicated by a dashboard light. In very cold conditions, cycle the glow plugs twice for better results. Avoid extended cranking (more than 15 seconds at a time); if the engine doesn’t start, wait 30–60 seconds and try again. Also ensure the air intake and fuel lines are clear of ice or moisture.
If you need to replace parts or problems persist, you can Order Parts Online Now or Schedule Your Service with at your nearest Koenig Location.