Why won’t my diesel Volkswagen start in the cold?

By Product Expert | Posted in Brand Information, FAQs, Tips & Tricks on Monday, December 16th, 2019 at 6:18 pm
car driving through snow

How Cold Weather Affect Diesel Engines

Have you ever seen a car parked in a driveway that has a plug-in hanging from the grille? Or maybe you bought a diesel, went out to start it, and it wouldn’t turn over. You may have even tried to jump it, to no avail.

Don’t worry. None of these situations mean your vehicle is broken. It’s actually completely normal. Let us explain.

Here’s why your diesel Volkswagen won’t start in the cold.


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diesel gas cap

Diesel Engines Don’t Have Spark Plugs

Diesel molecules are different than regular gasoline. Due to this, diesel engines work differently from gasoline engines. A diesel engine compresses air, which heats the air up, and then injects the fuel, which is ignited by the compressed, heated air. A gasoline combustion engine injects fuel and air simultaneously and ignites the mixture with a spark plug. The big takeaway from this is heat. A diesel engine requires the compressed air to be a certain temperature in order to ignite the fuel. When weather is cold, the air may not reach proper operating temperatures. Engine heaters are required for diesel engines to work in cold weather, and they need electricity to operate.

Get an Engine Block Heater

Many newer diesels come with a built-in engine block heater, but older cars may not. They usually need to be professionally installed, as an improperly placed heater or power cable could cause the heater to not function as intended or even damage your vehicle. The downside to this, of course, is that access to electricity during colder weather is necessary for diesel vehicles. While this may not be a problem at a private residence, if you have to stay at a place with public parking, like a city apartment or hotel, it may be difficult to find access to electricity.

Battery Failure

Like combustion vehicles, diesel cars have electrical equipment, such as the glow plugs and starter motor, that start the vehicle. If your battery can’t provide enough juice to operate them at full capacity, your car may not start. This can be temporarily fixed by charging your battery, either with a charger or through jumper cables. However, if this is a regular issue, a new battery is required. Getting a battery with high cold-cranking amps (CCA) and high capacity will ensure that your vehicle always has the electricity it needs to start properly.

Does Your Ride Need Some Winter Gear?

We have access to genuine OEM parts, and can install them for you. If you’re looking for some winter weather gear, like all-weather mats for instances, check out our genuine VW accessories.

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