With a price difference that exceeds 10% between normal and special diesel (each oil company names them in one way). You have to think very hard whether or not it compensates for this extra expense. Although it is true that performance improves, there are other drawbacks besides the price.
Is it worth the expensive gas oil or not?
When we are going to refuel our vehicle, at the gas station they give us many options: Diesel Plus, Diesel E10 +, Diesel V-Power. Actually, they can call it in a thousand ways. In the end, most drivers do not want messes of nomenclatures and distinguish them by the impact on their pocket. As with gasoline of 98 or 95, many drivers have doubts about which of these fuels to use in their diesel car and they need to know if it is worth the expensive oil or not.
In the advertising of many gas stations they talk about lower fuel consumption, more power and other benefits for mechanics, especially to avoid breakdowns in the diesel particulate filters. It is not that this advertising lies, but they are half-truths and the reality is that it is not usually worth the use of expensive diesel.
Yes, it is true that with the special diesel the car spends less. I have achieved differences of consumption in my tests between 5 and 8%. However, this does not mean a net saving, since the difference in consumption in favor of the most expensive fuel is clearly lower than the price difference between it and the normal one. That is, although we spend 8% less diesel, we continue to pay between 10 and 15% more for each liter so that in the net we continue paying between 2 and 10 percent more for each kilometer traveled.
It is also true that expensive diesel improves engine performance and we gain some power. Although not as much as the “place effect” after having paid more to fill the tank.
The main advantage is in cars that mount a particulate filter in the exhaust system. The special diesel causes more heat when burning and, being more refined, generates less waste in its combustion. These two factors reduce the chances of faults in the filter – known as FAP or DPF – but, in return, new problems arise.
Expensive diesel fuel can generate faults
The high-pressure pump and the injectors wear out quickly as the lubrication deteriorates. If you have ever stained your hands with diesel while you fuel at a gas station, you will notice that it takes a long time for the smell of the skin to go away and that it also has an oily feel. In fact, diesel has certain lubricating properties. Gasoline is the opposite, it evaporates quickly and does not leave that unctuous touch.
Expensive diesel is a fuel more refined than normal and is almost halfway between normal diesel and gasoline. Its lubricating properties are much lower and this drastically shortens the life of elements that are in direct contact with the fuel and that must be lubricated by it.
Read also: How to take care of your car properly
Parts such as the high-pressure pump, the injectors, the rail pressure regulating valve are more prone to damage if we use expensive diesel than normal. What’s more, if our car is a few years old and it is not a common rail, but it assembles injection pumps (especially the Bosch VP44 ), using this type of fuel is buying all the tickets for mechanical failure.
To get an idea of the price of the faults that can be caused by the worst lubrication of this fuel, an injector of a current diesel engine has a unit price (one in each cylinder) that exceeds 800 euros in most models.
As in the report on whether it was better gasoline 98 or 95, is that it does not pay to pay more for the special diesel. My advice is that you only use it if you are going to make a long trip or with the car loaded and you may be interested in that small performance advantage, but that you try to use regular diesel more frequently and, if your car is not a common rail and its injection system is by injection pump, better never use it.