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How to Start a Diesel Car or Truck

Because automotive engines powered by diesel ignite in a different way to those powered by petrol, the process for starting a diesel engine has some distinct differences.

This section explains the best way to start a diesel engine and why the fuel needs to reach a certain temperature before cranking diesels in cold weather.

Basic Steps for Starting a Diesel Engine

When you turn the key, the spark from a spark plug ignites the fuel in gas powered engines.

Whereas, a process of compression creates a certain amount of heat needed to get diesel engines ignited.

Simply put, once the fuel and air is hot enough it creates combustion - creating a spark to start the engine.

So, the process for starting a diesel car is different from starting one with an internal combustion engine (ICE). The next section breaks down the recommended steps required to start a diesel car or truck - especially when it's cold.

1. Diesel 'Wait to Start' Light

The first step for starting a diesel is to turn the key to the start position. It is important not to turn on the engine at this point.

You should then look for the 'wait to start' glowplug indicator light to appear on the dash. Wait until the light goes out before you attempt to start the engine.

2. Heating the Glow Plugs

The best way to start a diesel engine - especially when the air is cold - is to wait for the glow plugs to heat up. It usually takes glow plugs ten (10) to fifteen (15) seconds to get hot. So, you should be patient before turning the key to the 'full position' and attempt to get the vehicle running.

Once you understand glow plug principles, you will realise that the 'wait to start' light stays lit until the glow plugs are ready. Thus, the indicator may take longer to go out (heat up) if the weather is cold.

3. Cranking the Engine

The next step is to turn the key to the correct position for starting the engine. Allow it to crank for up to thirty (30) seconds and then turn the key to the 'off' position if you don't get the vehicle started.

Even though you can repeat the same steps again if it doesn't start, it may be worth reading the section about how a diesel engine works to get more information.

5. How to Start a Diesel Truck

Follow the same steps as outlined for starting a diesel car. If the truck engine fails to start after cranking for up to thirty seconds, turn the key back to the off position. Assuming there is no combustion, you could try: