You suspect a diesel leak on your Ford Mondeo , after noticing a stain that has formed on your parking space as well as significant diesel fumes escaping from your Ford Mondeo. However you have no idea where the problem is?

Added to the fact that it is not environmentally friendly, and with the current price of fuel, when you have a leak it is often not a problem to leave it lying around. Especially since the latter is generally accompanied by a particularly strong smell of fuel and it is not recommended to breathe this type of gas.
In addition, the fuel turns out to be a combustible material so it is not very careful not to clog it quickly.

Finally, a diesel leak beyond the particularly unpleasant fumes and the gasoline stain, will also be accompanied by overconsumption of diesel, loss of engine power and a feeling of jerk when you press on the accelerator after complicated starts. And finally it will damage the engine of your Ford Mondeo.

So to study the malfunction as quickly as possible, we will help you locate the origin of a fuel leak on Ford Mondeo.

We will start by helping you know by what means the diesel circulates on Ford Mondeo . Then we will tell you how to find a diesel leak on Ford Mondeo . When you have located where the leak is coming from, we will give you details the reasons for a diesel leak on Ford Mondeo .  

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1-How diesel circulates on Ford Mondeo 

In order to find the fuel leak on your Ford Mondeo, it seems useful to understand the path that the fuel follows inside your vehicle. This will help you identify the problem more quickly.

To be supplied with fuel, your Ford Mondeo is equipped with a tank which is located at the rear of your vehicle. Before it was located at the front to reduce travel, but now in order to reduce the risk of fires, it is attached to the rear.

Generally it is between the 2 rear wheels. This secures the tank in the event of an impact. Because if you have a collision and the tank spills it spreads a flammable substance and it can quickly be dangerous.

Then this tank is fitted with a fuel pump or also named feed pump ou booster pump . It is installed inside the tank and will send fuel into the pipes to deliver fuel to the front of your Ford Mondeo.

Thereafter the fuel will be filtered by the fuel filter to remove debris and particles that could be encrusted inside the tank.

After that the fuel will reach the injection device of your Ford Mondeo which also contains an injection pump. Usually in the latest versions there are high pressure injections. The latter will supply pressurized fuel to the cylinders which will be mixed with air so as to create the energy to operate the engine. The fuel will be transformed into gas inside the combustion chamber and will escape through the exhaust valves.

In short, the fuel will cross a certain distance between the tank and the engine and pass inside several components. This is the reason why the diesel leak analysis may be a bit complicated.

However, we will help you detect it and understand the source of this leak.

2-How to find a diesel leak on Ford Mondeo?

In order to understand the source of a diesel leak it is necessary to analyze the signs. Indeed, finding the leak will be very important because it will tell you which elements could be impacted. Also knowing if the leak is spilling with the engine running or off will also be quite revealing.

2. 1-Locate the diesel fuel leak on Ford Mondeo:

If you notice a halo of diesel under your Ford Mondeo as soon as it is parked, try to find if the leak is at the front of the car or at the rear. This will make it possible to identify whether the leak is in the tank or in the injection system.

Otherwise if it is not located at the ends it is possible that the leak comes from the hoses which connect the fuel pump, to the injection pump via the fuel filter.

2. 2- Check when the diesel leak is flowing on Ford Mondeo

When the diesel leak occurs when you are driving your Ford Mondeo, it is likely that the malfunction is due to the injection or an air intake inside the suction circuit. The latter could cause a diesel leak as soon as the pressure is put on. To analyze this hypothesis, you can open the hood and rev up to identify the leak. Check the connections around the high pressure line and the injector.

Small warning in case the malfunction comes from the high pressure pipes, these elements are rather dangerous, so before examining it, it is advisable to wait a certain time just after stopping the engine of the car.

If the leak leaks when you fill the tank of your Ford Mondeo, be aware that there may be too much diesel inside the tank.

Finally, if you perceive the leak when your Ford Mondeo is parked, it may be that the problem comes from a leak in the hoses or the connection joints.

3-The causes of a diesel leak on Ford Mondeo

3. 1-The diesel leak is located in the center of the Ford Mondeo: Problem with hoses or seals

Be aware that fuel runs through a number of lines and components that are sealed with the help of gaskets, but over time, oscillations, changes in temperature, the gaskets may not be as effective.

Another possibility in order to circulate the fuel will pass through hoses, so again with the movements of the car or the engine it is possible that they will disconnect and be the source of the leak.


Therefore if you are in this case you should check the seals and hoses to find the leak. Repair costs will not be particularly expensive, allow less than 100 euros.

3. 2-The diesel leak is at the rear of the Ford Mondeo: Fuel tank problem

The tank will store fuel to give you a little autonomy. So when you drive the booster pump will extract diesel inside the tank in order to send fuel to the front of your Ford Mondeo in order to re-fuel the engine.

If the tank is involved you will smell a strong smell of fuel inside your Ford Mondeo. The origin of the malfunction can come from the tank cap because it does not close properly, or from the fuel pump and why not from a hole inside the tank.

Generally the concern will be at the level of the gasket of the booster pump, you will hear a hissing sound coming from the tank. Or it could come from a hose connecting it to the fuel system.

It is also possible that there is too much diesel. Note that it is recommended to stop filling the first click of the fuel pump, after the 1nd click you run the risk of clogging the tank and it will flow through a hose intended for that.

3. 3-The diesel leak is located at the front of the Ford Mondeo with the engine running: Injection problem

When the leak is in the front of your automobile, it is often a problem with the injection system.

Indeed today most cars are equipped with high pressure injection, which is more efficient in terms of fuel combustion and gives better engine power. However, this weakens the system which is constantly under great pressure.

Here it is particularly advisable to make repairs to a garage because with the pressure and fuel splashes it is necessary to carry out the repair with vigilance.

A number of issues could be causing it. This could be the disconnection of a hose or the premature wear of the O-rings. In this case, you will have maybe, for a hundred euros for replacement of the seals.

Otherwise it could be a malfunction of the injection pump which no longer supplies the right amount of diesel or a reduction in pressure.

Furthermore, if the fuel filter is clogged and the injection system receives impurities, then the clogging of the injectors could generate significant impacts.

A concern inside the injection device is not trivial, prices will quickly rise, plan around 1000 to 3000 euros if it is necessary to change the pump or an injector.

Finally : A diesel leak could have various reasons. First you need to find out if it is at the front or at the back. When the concern comes from a hose the repairs will not be particularly expensive. On the other hand, if the malfunction comes from the injection system, it will generally be more expensive. In all cases, you will have to go to a concession as soon as possible.

Consulting : regularly check the diesel filter because it will prevent dust from entering the injection system, which is particularly fragile and will prevent you from leaking.

To go further in the maintenance of your Ford Mondeo, we invite you to consult our other pages on the Ford Mondeo.