Why Does My Car Keep Stalling?

Ellie Dyer-Brown, 4 months ago

5 min read

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

It can be worrying when your engine cuts out unexpectedly, and it’s even worse if this happens in the middle of your journey.

As you will already know, there are a few situations where stalling can occur without an underlying problem - for example, if you stop the car without putting it in neutral. However, when your vehicle is stalling frequently and your driving skills aren’t at fault, there may be an underlying problem with your car.

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 because the engine has stopped working. When this happens, you will often experience a jolt accompanied by engine warning lights on the dashboard, but sometimes, stalling can be more gradual.

Woman looking under the bonnet of her car.

The result is that you have less control of the vehicle, and if your engine won’t restart, you could be stranded in the middle of the road. If you find yourself in this situation, there are several things you can do to ensure your 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.

A broken down car with a warning triangle placed on the road in front of it.

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. This guide provides more detailed information about what to do when your car breaks down.

Once stationary, wait a minute then try to start the car again. If your car won’t start at all, it’s time to call for roadside assistance.


Top reasons for cars stalling

Overheating

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

Man looking at the engine of an overheating car by the roadside.

There are several 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 quickly - 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, the appropriate engine warning light should signal this. You should never drive without enough coolant or an engine that is too hot, as this can cause serious and expensive damage. 

Instead, have your car inspected by a mechanic as soon as possible. Read this guide for more information about why your car might be overheating.

Fuel System Problems

Without a functioning fuel system, your engine will not run smoothly and efficiently - in fact, it might not be able to run at all. The following issues could be causing your car to stall.

1. Blocked fuel filter

Before any fuel reaches your engine’s combustion chamber, it must first be filtered for dirt and debris, which could cause 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.

Fuel filters should be replaced every 20,000 to 150,000 miles.

2. 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, your car will be unable to produce the required power, resulting in it stalling. 

A hand holding a fuel injector.

The average price of a fuel injector replacement or repair on WhoCanFixMyCar is £185.35.

3. Blocked air filter

Dirt and debris build up in the air filter over time, resulting in a lack of air in the combustion chamber. When this happens, your car is likely to stall because the mixture of fuel and air must be correct for combustion to occur.

4. Clogged 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. 

Diesel particulate filter car computer message.

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, clean the DPF manually or replace it. 

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

The average price of a DPF clean is £188.29 when booked through WhoCanFixMyCar.

ECU Error

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

The average price of an ECU repair booked through WhoCanFixMyCar is £154.23.

Faulty Alternator

If your alternator isn’t working correctly, your battery won’t recharge while you drive, causing your car to stall. 

Two hands holding a car alternator.

There are many signs you can look out for indicating your alternator is on the way out. For example, your headlights might appear dimmer than usual, and your car's electronics might need to be fixed or will only work intermittently. If you notice any of these symptoms, take your vehicle to a mechanic who can check your alternator and battery and, if necessary, make a replacement. 

On average, alternator repairs cost £438.61 when booked through WhoCanFixMyCar.

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. 

Clutch

Clutch replacements usually cost around £624.58.


Driving a car

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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Written by Ellie

Ellie Author Pic

Ellie is WhoCanFixMyCar’s Content Writer. She has a BA in English literature from Durham University, a master’s degree in creative writing, and three years of experience writing in the automotive industry. She currently drives a Suzuki Swift.

Find Ellie on LinkedIn.