Wrong Fuel In Diesel Car Myth 1
Over the next few weeks we’re going to be looking at dispelling those wrong fuel in diesel car myths. The internet is a brilliant source of information but not all of it is correct and not all of the advice that you may find is beneficial. We have found many websites and forums offering advice to drivers who have put in the wrong fuel after asking questions about their best course of action. We’re going to ask the same questions, but our advice comes from expert engineers who have been removing the wrong fuel from cars and vans for many years and know their jobs inside out. All of our engineers are trained to be able to deal with modern and older vehicle engines and they have a lot of hands on experience to rely on. So, lets take a look at one of the most popular wrong fuel in diesel car related questions:
The Myth: If I have put some petrol into a diesel engine, is it OK to top up the tank until it contains mostly diesel and then just drive the vehicle until the petrol has been diluted out of the fuel system?
We have seen this question crop up in various slightly differing forms, again and again. The BAD advice also varies, with some people on the internet saying that it’s OK to put 10% to 20% of petrol in a diesel car, as long as you top it up with diesel, and others saying that if it starts and drives with a mixture of petrol and diesel in the tank then it’s fine to drive the vehicle until all the petrol has been used up. The truth is that NO amount of petrol is OK in a diesel motor.
Why is petrol so bad for a diesel fuel system?
Petrol is just about one of the worst substances that you could put into a diesel fuel system. The fuel systems on petrol and diesel engines are designed to operate in totally different ways as petrol and diesel are totally different fuel types. Diesel is much more oily than petrol and has a lubricating characteristic that a diesel fuel system relies upon. Petrol is a solvent with no lubricating qualities. A diesel engine has a much higher compression ratio than a petrol engine and therefore higher temperatures needed for diesel fuel auto ignition. Higher compression ratios mean better thermal efficiency and so, lower fuel consumption. Petrol engines feature much lower compression ratios to prevent fuel auto ignition. When you consider that petrol has been introduced to extremely high temperatures when it is mistakenly put into a diesel engine, you can begin to see why there might be an issue here with wrong fuel in diesel car situations.
What effect does petrol have on a diesel engine?
In a diesel engine fuel system there are several metal components that come into contact with one another. They rely upon the diesel lubrication to prevent damage or heat build up due to friction. If the diesel fuel lubrication is compromised by the introduction of petrol to the system, then friction damage will occur to these components. The heat build up will make them wear out faster and the lack of lubrication will result in tiny particles of metal being worn away from the component surfaces and getting into the fuel flowing through the system. This fuel makes its way to the fuel injectors. The fuel should then be injected into the cylinder block but the injector may either be partially blocked resulting in reduced engine performance, or in the worst case scenario, completely blocked which could mean that the injector is damaged and needs replacing.
How bad is the worst case scenario?
Well, if you own a premium motor such as a Mercedes, BMW or Jaguar, then a wrong fuel in diesel car situation is BAD. Fuel injectors for these brands are expensive, as are most fuel system components. Expect to pay around £300 for each injector in a BMW 520 diesel and then £300 to £400 for labour to change them. Even if you drive something much more modest such as a Ford Focus, you’re still looking at between £200 and £250 per injector plus a day’s labour. In addition to potential injector damage, as petrol is a solvent you are also seriously at risk of damage to the seals in the fuel system components. This could result in the need to replace the fuel pump, filter and fuel lines. If you take your motor to a main dealer to honour the warranty on your vehicle, then you will be hit with a large repair bill. They may even require replacement of the entire engine.
In short, don’t drive your diesel car with any amount of petrol in the fuel system. A low cost fuel drain will put everything right and won’t end up costing you a fortune in the short or long term. Call our expert team to deal with your wrong fuel in diesel car problem and we’ll end up saving you a packet.