What Actually Happens When You Use The Wrong Fuel In Your Vehicle?

Fuelling your vehicle is one of the regular chores that just needs to be done. After years of owning a vehicle it can be very easy to not dedicate your full attention to how you’re fuelling your vehicle. Also, if you are in a rush, or you are visiting a new petrol station, it can be very easy for mistakes to be made. Around 150,000 drivers every year end up putting the wrong fuel in their vehicle in the UK. It’s a surprising statistic, but the fact of the matter is that fuelling mistakes are easily made, and the effects of such a mistake are widely unknown to the average driver.

So, you may be wondering -what actually happens when you use the wrong fuel in your vehicle? Putting the wrong fuel in the car is a relatively easy situation to rectify. Calling out a professional fuel removal service such as Wrong Fuel Expert will mean that your vehicle will have the wrong fuel extracted and the lines flushed in a matter of no time. However, knowing what the wrong fuel actually does to your vehicle mechanically may help to know if your vehicle is seriously damaged. It may even contribute to preventing putting the wrong fuel in your vehicle in the first place.

When you use the wrong fuel in your vehicle, the extent of the damage or problems depend on a number of factors. The extent of the issue will depend on the age of your vehicle, your vehicle’s engine and which wrong fuel you used to fill your tank. Firstly it’s important to know the difference between diesel and petrol engines. A diesel engine relies on ‘compressions ignition’, which is an internal combustion that uses the heat of the compression to ignite and burn the fuel that has been injected into the combustion chamber. This is the process that happens to make your car go faster.

Petrol engines on the other hand, generate far lower combustion ratios. Petrol engines don’t need to build that much compression in order to burn the fuel. They rely on an electric spark ignition, which uses a spark plug to ignite the air-fuel mixture and create an explosion. This is the same reason why some use a spark plug at the tip of their exhaust as a small ‘flame thrower’. The expansion of the exploding gases hits the top of the pistol and causes it to be blown downwards, turning the crankshaft and supplying the rotary motion out of the engine.

So, when petrol is put in to a diesel engine this can either mean that the engine will not ignite, or worse, ignite at a bad time that could potentially cause an explosion within the engine. The high compression of a diesel engine will cause the petrol to auto-ignite. The other problem is that gasoline also burns faster than diesel, so you have a high compression ratio plus a very high peak pressure of burning petrol, the pressure being higher than it would be if burning diesel. This puts a lot of stress on the engine and may cause it to explode.

However, if you put diesel in a petrol engine your car will have an entirely different reaction. Diesel is heavier than petrol and much more “oily”. It needs a high pressure in order to be ignited and it doesn’t evaporate in the way that gasoline does. When you put diesel in your tank by mistake the fluid will sink and the injectors will feed the engine a dose of diesel instead of petrol. At this point, when you try to ignite the engine, the spark plugs won’t be able to fire the diesel and the engine won’t start at all.

This is a much easier problem to rectify as people notice there is a problem much quicker as their vehicle won’t start at all. A fuel removal company will drain the tank and fill it again with petrol. The injectors will be cleaned and cranking the engine to dispel unwanted diesel should rectify the issue. Sometimes it may be recommended to change the fuel filter, depending on the situation. Despite the limited damage that is usually caused to most petrol engines, some Gasoline Direct Injection (GDI) petrol engines are particularly susceptible to damage and may require further repairs. However, the destructive nature of petrol in a diesel engine may mean that internal components may be permanently damaged and the engine may experience a complete block.

Driving a diesel car filled with petrol could irreparably damage its more sophisticated engine – and in the worst case scenario, metal particles from the engine could get into other parts of the fuel delivery system causing even more damage. This is exactly why you are strongly advised not to start your vehicle, or to stop as soon as possible once you have realised you have put petrol in a diesel engine. Metal particles from the damaged pump can be deposited in the fuel causing further damage to the rest of the fuel system. Common rail (or HDi) diesel engines are particularly vulnerable – if fuel contaminated by pump wear debris gets as far as the common rail system you may have to replace the low and high-pressure fuel pumps, injectors, fuel rail, line filters and the fuel tank. Even the fuel system seals can be affected by the compounds in petrol.

If you are concerned about the damaged that is being caused to your vehicle due to using the wrong fuel, call Wrong Fuel Expert immediately in order to prevent permanent damage to your engine.