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What to Do If Your Bus Won't Start on a Cold Day

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Diesel engines are typically fitted to a bus or coach, due to their reliability and capacity to deal with all manner of situations. They will usually perform very well no matter how many trips the vehicle performs on a given day or how many days of the week it is pressed into service. However, they can run into problems, and you may find it difficult to start the engine on one of your vehicles, especially if the ambient temperature is quite cold. If you've been having a problem starting one of your buses for those early morning winter school runs, what could be going wrong?


While diesel engines are known for their endurance and are well engineered to cope with the associated demands, you have to make sure that you are using the right type of oil for the situation. Certain lubricants may become too sticky when temperatures flirt with the freezing point and this could cause an increase in the amount of drag when the driver is trying to fire it up. In this case, he or she would not be able to generate enough fuel pressure or compression within the crankcase to get everything going. To remedy the problem, take the vehicle into a service bay and change the oil for a lighter solution that is designed to help improve cranking performance in cold weather.


At the same time, the technician should check the condition of the battery and the connections to ensure that the starter is getting the right power and can contribute to the operation.


Attention should also be given to the glow plugs fitted. There will be several of these on each vehicle, and they are designed to assist during a cold start, but each one should be checked to see if it is still active. The plug is supposed to function for a given amount of time, and this is controlled by a timer and relay system to ensure that the correct voltage is applied. If there is an issue with one of the relays, then the glow plug may have become overloaded and might have burned out.

Down to Work

A skilled technician will be able to look at these and the other potential issues to determine why you're finding it so difficult to start your bus on a cold day. Make sure that you give them all the symptoms and issues so that they can figure it all out. Reach out to a bus repair company to learn more.