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Why does my car keep stalling?

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WhoCanFixMyCar explains why your car might be stalling and what you can do to fix it.

It can be quite scary when your engine cuts out unexpectedly, and it’s even worse if this happens in the middle of your journey or on a busy road! 

As you will already know, there are a few different situations in which stalling can occur without there being an underlying problem. For example, if you stop the car without putting it in neutral or try to set off in a gear other than first you will probably experience the uncomfortable jolting sensation that comes with an engine stall.

As such, stalling is a common problem encountered by learner drivers, but if your car is stalling frequently and your driving skills aren’t at fault, this indicates an underlying problem with your car. 

Even if you haven’t experienced an unexpected engine stall - we hope you never do! - it certainly pays to be prepared, which is why we’ve created this guide. In it, you can find some of the most common problems that might be causing your car to stall, as well as advice about what to do if disaster strikes and your engine fails at the worst possible moment. 

Guide Contents:

What happens when your car stalls?

What to do if your car stalls

Top 5 Causes


What happens when your car stalls?

Stalling refers to the moment when your car comes to a stop by itself. When this happens you will often experience a jolt accompanied by engine warning lights on the dashboard, but sometimes the process of stalling can be more gradual. 

When this happens you will have less control of the vehicle, and if your engine won’t restart at all, you could be stranded in the middle of the road. If you find yourself in this situation, there are a number of things you can do to ensure your own safety and the safety of other road users.


What to do if your car stalls

Finding yourself stranded with a car that has stalled and won’t restart is most drivers’ worst nightmare. The most important thing is to keep calm and do all that you can to make the situation safe. 

Firstly, put your hazard lights on to make other road users aware of what is going on. If your car is still coming to a stop, try to use this momentum to reach a safe place away from traffic, such as the side of the road, a layby or the hard shoulder.

However, if you’re unable to do this and are stopped in traffic, don’t try to exit the vehicle as this could result in an accident. 

Once stationary, wait a minute then try to start the car again. Even if it starts as normal and you’re able to drive away, you should seek mechanical assistance as soon as possible to find out why your car stalled in the first place.

If your car won’t start at all, it’s time to call for roadside assistance.


Top six reasons for cars stalling

Overheating

When your cooling system fails, your car’s ECU will eventually force the engine to stall once it reaches a certain temperature to prevent serious damage. 

There are a number of reasons why your engine might be overheating, including a coolant leak, a faulty water pump or a blocked radiator. 

You should be able to detect a coolant leak fairly easily yourself - cracks will often be visible on the pipes leading to the radiator, and if you run the engine you will probably be able to spot leaking coolant. A humming sound at the front of your engine also indicates a leak. 

If your car is overheating then the appropriate engine warning light should come on to signal this. You should never drive without enough coolant or with an engine that is too hot as this can cause serious damage that is expensive to repair. 

Instead, have your car checked over by a mechanic as soon as possible. 


Fuel System Problems

Without a functioning fuel system, your engine will not be able to run smoothly and efficiently - in fact, it might not be able to run at all!

First thing’s first, check your fuel gauge. It might sound obvious, but if there’s no fuel in the tank then your engine can’t run. We’ve all been there, and while it’s not an ideal situation, at least there’s an easy fix. 

However, if you have plenty of fuel in the tank, the problem might be a little more serious.

  • Blocked fuel filter - Before any fuel reaches your engine’s combustion chamber, it must first be filtered for dirt and debris which could cause serious damage. Over time, your fuel filter can become clogged, and when this happens it restricts the amount of fuel that can reach the chamber. If there isn’t enough, your car will stall due to a lack of power.

  • Faulty fuel injectors - Fuel injectors introduce fuel to the combustion chamber. The amount of fuel must be precise for combustion to occur correctly; if there is too much or not enough then your car will be unable to produce the required power, resulting in it stalling.

  • Blocked air filter - The mixture of fuel and air must be correct for combustion to happen within your engine. Dirt and debris will build up in your air filter over time which can eventually result in a lack of air in the combustion chamber. When this happens, your car is likely to stall.


Faulty DPF

The DPF (diesel particulate filter) is designed to combat harmful emissions from diesel engines. Going on many short journeys can cause the DPF to become clogged because it does not reach a high enough temperature to work efficiently. 

Blocks in the DPF can cause back pressure, making the vehicle lose power and sometimes stall. In this situation, there are three possible courses of action. You can force a regeneration, remove the DPF to manually clean it or remove and replace the filter. 

It’s worth noting that DPFs are not designed to last the whole lifetime of a car, so if you’ve had yours for a number of years it might be worth looking into a replacement filter. 


ECU Error

The ECU, or engine control unit, can sometimes cause your car to stall if it incorrectly detects a mechanical error. This is supposed to prevent an accident, but if there’s no real fault it can be frustrating. The best thing to do in this situation is to take your car to a mechanic to have the ECU examined and fixed as necessary.


Faulty Alternator

If your alternator isn’t working properly then that also means your battery won’t be recharging while you drive, causing your car to stall and the engine to die. 

That being said, there are many signs you can look out for before your alternator gives up completely. Your headlights might appear more dim than usual and the electronics in your car might not work properly, or will only work intermittently. If you notice any of these symptoms, take your car to a mechanic who will be able to check your alternator and battery and, if necessary, make a replacement. 


Clutch and Gearbox Problems

The gearbox and clutch are both prone to wear and tear after extensive use, and any damage is likely to cause your engine to seize up and stall. If you notice that it’s more difficult to get your car into gear or if it feels like your clutch is starting to slip, it’ll only be a matter of time before these problems get worse, so the sooner you head to a garage the better. 


Sometimes, stalling is simply the result of human error. We can’t all be perfect at driving 100% of the time, but if your car starts stalling unexpectedly, WhoCanFixMyCar is here to help you find reliable local repairs that won’t break the bank.

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