Diesel in winter - facts and myths

Diesel in winter - facts and myths – main image

Most motorhomes are equipped with diesel engines. And there is a lot of "folk wisdom" about using diesel cars in winter. Not all of them need to be believed.

In winter, it is better to refuel under the cork - FACT!

The less fuel in the tank, the greater the chance of condensation in it. In winter, this can mean serious problems. Also, when we refuel the car frequently, adding little fuel each time, we increase the risk of air getting into the tank. The air condenses to water, the water turns to ice, and the fuel filter or fuel line is blocked. More water is also a risk to the fuel pump and injection system.

The interior of a diesel car heats up slower - FACT!

Diesel engines emit less heat to the outside than gasoline-powered engines. The result is that heating seems useless for short journeys. When the frost is severe, it takes 20 minutes or more for hot air to flow in. Fortunately, many motorhomes are equipped with auxiliary heating, thanks to which we can get into a heated vehicle right away.

Starters and batteries are particularly at risk in winter - FACT!

The lower the temperature at which the engine is started, the thicker and therefore less fluid the consistency of the diesel fuel. In frosty conditions, the starter has to do its best to start the engine, which in turn is a challenge for the battery as well. Besides, if the car is equipped with auxiliary heaters, that also means effort for the battery. Therefore, in diesel cars you should use different batteries than in gasoline cars and take care of their condition on an ongoing basis.

Replace the fuel filter before winter - FACT!

If you own a diesel car, you can save yourself from trouble by replacing (or possibly cleaning) the fuel filter before the winter. This way you will minimize the risk that the contaminants collected in the filter will be covered with water droplets that will freeze. Paraffin crystals also precipitate from the diesel fuel and can block the filter.

The bad condition of the glow plugs will prevent the vehicle from starting in winter - FACT!

Glow plugs that were good enough to start the vehicle in positive temperatures may turn out to be too weak in severe frost. The risk is not high, and any damage is usually indicated by the indicator on the instrument panel, but before the onset of severe frosts, it is worth making sure that the candles are in good condition.

Diesel - as a rule - difficult to run in the cold - MYTH!

If all the car's components are in working order, and the tank has winter diesel fuel (it does not have to be "arctic"), in most cases the diesel engine starts as easily as the gasoline one. Of course, remember to wait a few seconds for the glow plugs to heat up before turning the starter. Problems may arise only at temperatures lower than -20 degrees Celsius - then, indeed, special fuel can facilitate starting.

In winter, fuel enhancers should be used - MYTH!

Winter fuels (that is, all fuels sold in winter) already contain additives that reduce the density of diesel fuel in frost. Therefore, further additions are not needed and in most cases turn out to be useless.

When the fuel solidifies, use a depressant - MYTH!

A depressant can only be useful in one situation - when we have summer fuel in the tank and severe frosts are approaching (but not yet occurring). Then you can apply preventive measures to reduce the clotting of the oil. The depressant will not help if the fuel has already solidified. The car should then be put in a warm garage and, if necessary, the engine block and sump should be warmed up with an external electric fan.

Denatured alcohol will improve fuel properties in winter - MYTH!

While in old engines the presence of denatured alcohol should not be harmful, for modern constructions adding denatured alcohol or other substances that were not intended for cars can be lethal. They can damage the power system. At extremely low temperatures, you can possibly use extraction gasoline (but not regular gasoline!).

Turning on the glow plugs several times can make it easier to start a cold engine - MYTH!

Glow plugs in cars produced today are under the control of electronics, which ensures that the candles warm up to the appropriate temperature. So there is no need or possibility for them to heat up more than programmed. If the indicator light for glow plug heating goes out, it means that the correct temperature has been reached.


Sometimes it is better to get lost than to ask for directions too much. Aldous Huxley

Also read