Jump Start a Diesel Car: Can you? How? [Explained]

Diesel engines require a completely different kind of jump-start procedure to petrol (gasoline) engines. The reason for this is due to the higher compression ratio inside the diesel’s cylinders, meaning that you’ll need a lot more amps and a longer period of time to get it started.

If you’re driving a diesel car, then there’s a chance that you might be able to jump it. Diesel cars are different than gas-powered vehicles in many ways, such as how they start-up and what kind of fuel they use. One thing they have in common with gas-powered vehicles is the need for jumper cables to get them going again when their battery dies.

You don’t want to find out on your own that your car won’t start because you didn’t know this little bit of information so check out this blog post before you go anywhere without jumper cables.

Table of Contents

Can you jump-start a diesel car?

The answer is yes, a diesel car can be jump-started. The first step to jump-starting a diesel car is finding another one with jumper cables so that you can hook them together. After both cars are hooked up to each other, put the other vehicle in neutral and turn both cars on. Let the running vehicle idle for a few minutes before turning it off.

Jumper cables should only be used if you are sure that a diesel car can be jump-started. If a diesel car is hooked up to jumper cables incorrectly or with bad batteries, it will have major problems starting every time until the system is fixed by a professional mechanic. Diesel cars are different than gas-powered vehicles so it is always best to check in with your manual before attempting anything of this nature.

How do you start a diesel with a dead battery?

These are the steps to start a diesel engine with a dead battery:

  1. First find a power supply to connect to your battery or use jumper cables.
  2. If you are using jumper cables, make sure that the ends are clean and without corrosion. Make sure you connect the positive (red) cable to the positive terminal on your dead battery and the negative (black) cable to the negative terminal. Connecting two terminals can result in sparking or arcing and potentially damage your battery terminals so be careful with this step.
  3. The cables should be connected in this order. Once your battery has been properly connected, start your vehicle.
  4. If you have a gas or petroleum powered engine, it can be more difficult. You will need to locate the battery and find the battery compartment near the bottom of the engine block.
  5. Take out all cables until they are disconnected from their terminals and disconnect the negative (black) cable from the terminal.
  6. Next, find a power source that is 12 volts or higher and attach one end of your jumper cables to the negative (black) cable of your dead battery. Connect the other end to your power supply as this will create a ground for your engine block. Once you have connected these cables, start your engine while it is still attached and running on its power source.

All vehicles should now be able to start up successfully and run normally.

Do you need different jump leads for diesel?

Yes, you need a different type of jump lead for diesel. It is advisable to use the same cross-section as for your alternator cable, e.g. 35mm2 – 50mm2 for a diesel car with an 80A alternator.

This will give the battery sufficient starting current for cold starts and also be able to cope with the high currents in a diesel car.

How long does it take to jump-start a diesel truck?

The purpose of jump-starting a diesel truck is to start the engine and let it run for several minutes so that the diesel battery can charge. Because diesels are made with special batteries, it will take about 10 to 15 minutes to charge a diesel truck.

Which battery do I jump on a diesel?

Since diesels have dual batteries with cables of the same thickness, it doesn’t matter which one you choose.

Why do diesels have 2 batteries?

Diesel engines use a high resistance to get the engine started. Because of this, they have two batteries so that when cranking, both batteries can be working at full power. If only one battery was hooked up for starting, it may not be able to supply enough power.

Can a diesel engine start without a battery?

No, a diesel engine cannot start without a battery because they need the high resistance produced by batteries to start.

Can you start a diesel with one battery?

Diesel vehicles are usually started with a dual starting system. This means they have two batteries.

The answer is yes and no, it depends on how much energy is left in the good battery and if your alternator has enough power to recharge the dead battery while running. If you have a fully charged good battery and a low amount of charge left in the dead battery, it is possible to get your diesel started (if it starts at all) with one fully charged good battery. The engine probably won’t run very long and you will have trouble restarting if at all.

Can you jump a diesel with two cars?

Yes, you can jump a diesel with two cars, but it is not recommended!

I would NEVER recommend wiring two batteries in series to try and get more voltage for a starting attempt or anything else. This is very dangerous.

Can you use a diesel car to jump start a petrol car?

You can use diesel to jump-start a petrol car. Provided that the diesel car battery is fully charged. The current needed to start a petrol car from diesel is not too great and therefore, there shouldn’t be any damage done to the diesel engine or gearbox.


If you want to jump-start a diesel car, you will need the right type of jumper cables. You should use thicker cables (35mm2 – 50mm2) and make sure they are long enough for your vehicle’s size.

If all conditions are met, it is possible to get your diesel started with one fully charged good battery. However, if your engine doesn’t work when trying to start it or takes too much time before starting up on its own power source without any help from another power source then this is not recommended.