Alastair Shephard

Content Writer

Alastair Shephard | Author

Joseph Law

Bumper Content Writer

Joseph Law | Author

A blocked DPF (Diesel Particulate Filter) can cause serious engine issues, reducing power and increasing fuel consumption. 

Common symptoms include the DPF warning light, loss of power, black smoke, and poor fuel economy. This guide explains the signs of a clogged DPF and how to fix it.

A DPF filter captures harmful soot particles from diesel exhaust, holding them until they can be burned into less harmful ash through a high-temperature regeneration process.

 Since 2009, DPFs have been mandatory on 

A blocked Diesel Particulate Filter (DPF) is a common issue in diesel vehicles, with the flashing orange DPF warning light being the most obvious sign. 

But there are other symptoms to watch for, such as:

The most obvious sign of a blocked DPF is the illuminated 

 This indicates that the filter is clogged and may need to be regenerated or cleaned.

Loss of Engine Power & Sluggish Acceleration

If your engine feels sluggish and lacks the usual power, it could be due to a blocked DPF. This restriction can limit the engine's efficiency and performance, causing a noticeable loss of power.

A blocked DPF can prevent your engine from revving past a certain RPM. This is because the engine’s exhaust gases can’t flow freely, which can cause the vehicle to feel restricted.

When the DPF is clogged, incomplete combustion of fuel can cause 

 to be emitted from the exhaust. This is an indication that the engine is struggling to properly filter exhaust gases.

A clogged DPF can lead to starting issues, especially if the filter is severely blocked. If your vehicle struggles to start, it could be related to poor exhaust flow due to the blocked filter.

When the DPF is not functioning optimally, your vehicle may burn more fuel than usual, resulting in 

This happens because the engine works harder to push exhaust gases through the clogged filter.

In many modern vehicles, the start-stop function helps save fuel by turning off the engine when idling. 

A blocked DPF can cause this function to stop working, as the engine may need to stay running to maintain exhaust flow.

A strong smell of diesel inside the cabin could indicate that the DPF is not properly filtering the exhaust gases. This can result in unburned fuel entering the cabin, which can be harmful to both the driver and passengers.

Noticed some clogged DPF symptoms? Here are a few quick fixes for each problem.

If any of the issues above persist, a professional DPF clean may be necessary to restore optimal performance and prevent further damage to your vehicle.

You can use DIY techniques to tend to minor DPF problems. These basic fixes include driving at a higher speed and using a DPF cleaning additive.

While these can help clear blocked DPF symptoms, it’s best to consult a professional for thorough cleaning in case the blockage is significant. In a few cases, you may need a replacement, which is always best done by a professional.

What happens if you ignore a blocked DPF?

Ignoring a blocked DPF can lead to poor engine performance, increased fuel consumption, and potentially severe engine or exhaust system damage. 

These can even lead to costly repairs and reduced vehicle lifespan. Not ideal! If you think your diesel particulate filter is clogged, get it checked out as soon as possible. 

Luckily, you can avoid a clogged DPF. Here are the top 3 tips drivers need to know to ensure their diesel particulate filter isn’t clogged.

Sadly, diesel cars aren’t great if you only want to pop to and from the shops. 

The exhaust needs to be hot to burn off the soot. If it never reaches a temperature high enough, it will only become more blocked. 

To mitigate this, ensure at least once a week it makes a journey above 40mph for over 30 minutes, or more if possible. This is your sign to hit the motorway!

Special oils have been developed for use in DPF-fitted cars. These have lower element content to avoid soot buildup (e.g. Sulphated Ash, Phosphorus and Sulphur). 

You'll find these labelled low SAPS at any regular shop selling engine oil. For more information about oils, find out 

3. Take care of any other engine issues promptly

Diesels are generally more complex than petrol engines. They have more components that can fail and cause issues with DPFs. 

You should pay close attention to any issues on:

The above can cause excess oil or soot to exit the engine through miss-fueling or oil consumption. These will clog up a DPF in record time, so be on the lookout for 

How long does a DPF last before it needs replacing? 

A DPF typically lasts between 80,000 to 150,000 miles. This can depend on your driving habits and vehicle maintenance. 

Regular long drives help extend its lifespan, while lots of stop-start city driving may cause it to wear out sooner. 

A DPF replacement costs between £800 to £2,000.

DPF replacement costs are affected by the vehicle's make and model, the type of DPF required, labour costs, and whether the DPF is an aftermarket or original part.

Some garages specialise in replacement DPFs, but generally, most normal garages can remove and replace a DPF. 

With proper maintenance and regular longer journeys, a DPF can last up to 100,000 miles. So, don’t delay those road trips—frequent driving helps keep the DPF functioning well.

Yes, it’s illegal, and you’ll face an invalidated insurance policy and a fine (up to £1,000 for cars and around £2,500 for vans). 

Even if your diesel particulate filter is clogged, you should never remove it.

Think your DPF is clogged? Hopefully, this blog has helped you understand DPF clogs, the symptoms, and how to prevent this problem. While you hopefully won't face this pesky issue, knowing how to navigate it will help you save time if it happens.

If you need to fix your DPF and are worried about costs, Bumper is here to help.

, you can split the cost of DPF replacements and other repairs into monthly instalments, completely interest-free.

Choose from thousands of trusted and reliable repairers.

Is Your DPF Blocked? 8 Warning Signs and How to Fix Them

How to know if your DPF is blocked

¿Cómo saber si el Filtro de Partículas Diésel (FAP) está obstruido?

So erkennen Sie, ob der Dieselpartikelfilter (DPF) verstopft ist

An internal combustion engine produces significant amounts of heat. In all modern car engines, this heat needs to be controlled and this is done with water. The water pump then is a vital component. 

In this article, we’ll explain a little about what it does, and why it's important to be able to check if the water pump in your car is failing. 

A car's water pump cycles water from the radiator, through the motor and back again, in order to keep the engine at a constant temperature. 

As mentioned, the action of burning fuel inside an engine creates a lot of heat. Typically engines run at around 80-100°C. 

The coolant system uses fluid to move heat from the engine to the outside air. It does this by passing the hot water through the radiator. Car radiators are positioned to allow maximum flow of air over them, reducing the temperature of the coolant. 

The coolant then flows back through the engine and cools the entire system, the 

 depends on your climate and engine type. The water pump is what makes this fluid flow. 

If you’re concerned about your car’s water pump, there are symptoms to look out for. We’re going to go over the main signs of water pump failure. 

The first and foremost thing to check is engine temperature during operation. Many cars have a gauge with an acceptable temperature level and a red or dangerous level.

Ensure the needle of the temperature gauge never enters the red zone, if it does, stop driving the car immediately, as excessive overheating can cause serious damage. 

Check under the vehicle before and after every trip. It may be necessary to open the bonnet and look around the sides of the engine to spot any wet patches or recently damp areas. 

Bear in mind the engine will have been hot enough to evaporate small drips. Patches of rust around the pump are also an indicator it has been dampened at some point. 

It might be helpful to place a plain piece of cardboard or paper under the engine after you park up. Held down with some weights, this will make any drips very easy to spot, especially if you park your car on gravel. 

If the water pump is damaged, and the coolant is not flowing properly, it may boil and exit the system as steam at the expansion tank or radiator. 

If the engine has overheated to this point, do not drive any further than is absolutely necessary, more heating could damage the engine irreparably. 

If you have started to notice a noise such as scraping, or whining from the side of the engine, this too could be the water pump failing. In any case, any such 

should be properly investigated and the car not driven until fixed. 

How much does a water pump replacement cost? 

On average, you can expect to pay between £250-700 for a replacement water pump. Of course, the cost will vary depending on your car’s age, make and model. 

If you're worried about car repair costs, Bumper can help. We've teamed up with trusted partners around the UK to offer 0%-interest car repair loans.

How critical are the cooling system and water pump 

As we’ve discussed, coolant is used to move heat away from the engine, so what happens if your water pump fails? 

Without cooling, an engine can quickly reach 150°C and beyond. At these temperatures, plastics around the engine will begin to soften and become weak and wiring will melt and cause shorts, but most terminally, metal engine components can warp. 

The head and block are the two main components of an engine, between them is a head gasket, which seals against the pressure of the combustion chambers or cylinders. 

If the head becomes warped, it is likely a loss of pressure in the cylinders will result. The level of pressure in a cylinder is known as ‘compression’ and head warping and head-gasket failure are common causes of low compression.

Low compression will make the engine run poorly and inefficiently, and in many cases not run at all. A vehicle that has suffered a warped head or head gasket failure cannot be driven. 

how much a head gasket replacement costs.

If you experience any of the problems listed above or have noticed any of the warning signs, it's important to get your car checked over as soon as possible. Water pump failure can lead to irreparable damage to the engine, and it will leave the car stranded. 

When repairing the water pump it’s recommended to change your cam belt 

 On many cars with a cambelt, the belt needs to be removed to change the water pump, so it makes economical use of the labour time to do both at once. 

If you need any assistance with car servicing and repair costs, enter your vehicle registration and postcode with 

 and apply for interest-free monthly instalments for maintenance invoices. 

 has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.

4 signs your water pump is failing

4 Anzeichen, dass Ihre Wasserpumpe defekt ist

, cars fitted with ABS are 48% less likely to be involved in road traffic accidents than those without. It’s hard to put a number on the number of lives saved, but anyone with experience trying to stop in wet weather in a car without ABS knows how brilliant the technology is.

ABS enables inexperienced drivers to brake safely in wet conditions, with a much reduced risk of losing control or skidding. 

In this article, we’ll discuss how you know your ABS is working and signs it has a fault. We’ll also look at what ABS does and what to do if your ABS is faulty.

If you recently had to brake very harshly, particularly on a wet or gravelled surface, and you felt the brake pedal and front of the car shake slightly and heard a fast juddering sound, this is your ABS system working.

If your ABS light is on, you might have a fault in the system. Here are the four main reasons the light may appear:

Symptoms of an ABS fault are hard to pinpoint. If in any doubt you should always take the car to a mechanic to have the system checked, before continuing to drive. 

Here are three key ABS pump failure symptoms every driver should know.

The wheel speed sensors are often used by other systems, such as traction control, so the car's ECU constantly monitors the output. If any becomes faulty, the vehicle should display an ABS warning light on the dashboard.

One symptom is if your front wheels lock and skid upon hard braking. This can be heard easily if the windows are down but can sometimes be hard to hear in the cabin. The car will feel like it has suddenly hit ice, and the steering will be heavy but unresponsive until the brakes are released.

3. Brake power reduces under hard braking

If the ABS pump fails, braking power can disappear when the ABS activates, often going unnoticed until needed. Given the risks, have the system checked by a professional immediately if you have any concerns.

Before we continue, we’ll quickly recap what ABS means. 

An anti-lock braking system consists of a few key components not found in non-ABS-equipped vehicles. Its basic purpose is to prevent the wheels from locking or skidding under hard braking.

Modern brakes are very powerful. Without ABS, it would be easy for them to lock up the wheels under emergency braking conditions. This is especially important on wet roads.

It may seem counterintuitive, but releasing the brakes helps slow the car more effectively than skidding wheels. Steering also only works when wheels are turning, so ABS allows you to brake and steer simultaneously.

ABS systems are extremely beneficial to drivers. Here are some key advantages they offer:

The ABS system consists of three main components: an Electronic Control Unit (ECU), an ABS pump/modulator, and ABS sensors. 

All three parts, along with the standard braking system, need to be in good condition for the system to function properly. Here’s a quick breakdown of each.

An Electronic Control Unit is a computer that manages various vehicle functions by processing data from sensors and controlling related components. It oversees tasks like engine management, transmission control, and ABS operation.

The ABS modulator, or ABS pump, is a brake component that rapidly controls brake pressure to prevent wheel lockup. 

It uses a high-pressure pump and valves to adjust braking force in a split second until brakes are released or traction is regained. In many cars, the ECU and pump are integrated into one unit.

ABS sensors, or wheel speed sensors, are mounted at each wheel behind the brake disc or drum. They detect the spinning ABS ring (reluctor ring) on the 

 using a magnetic field, allowing the ECU to monitor wheel speed.

If a wheel locks up during braking, the ECU signals the ABS modulator to adjust brake pressure.

ABS can fail prematurely. Because of the relatively low number of parts involved, it is usually easy to diagnose but can be expensive to fix.

Common if the car has just had work done on a suspension component, 

 or wheel, the ABS sensors can be fragile devices, and a small knock whilst removing other parts can cause them to send faulty readings. 

An ECU diagnostic check should detect this issue, most cars will also warn of some kind of issue with a general ABS warning on the dashboard. ABS sensors range from £30-£150 each, and would usually take less than an hour to change.

An internal ABS pump fault may not always be detectable by software, but cars usually store an error code after a failed ABS attempt. 

ABS modulators can fail due to age or poor brake fluid, which can cause blockages in the valves. Regular 

ABS pumps can be costly, often over £1,000, but refurbishing options might be available. So, always consult your mechanic for advice.

For the ABS to work effectively, the rest of the conventional braking system needs to be in good working order. 

Common faults with the braking system can be a failed master cylinder, old or insufficient brake fluid, excessively 

It’s critical to consult a mechanic if your ABS light is on. However, you can also try these at-home checks first.

These DIY steps are just initial checks, and if you’re unsure, it's best to seek professional help.

The ABS is a miracle for modern drivers. Knowing how to check the ABS system is critical, as you want to ensure it’s working properly at all times.

If for any reason, you suspect your ABS, get your car to a garage as soon as possible. They will be able to perform diagnostic checks and ‘field tests’ to see if the ABS is working as it should. 

enter your vehicle registration and postcode

Apply for Bumper and split the cost of your repair bill into monthly instalments, at no extra cost.

How To Check if Your ABS Is Working

 Cómo comprobar si el ABS funciona correctamente

So erkennst du, ob dein ABS funktioniert

Twenty years ago, it was a simple choice: petrol or diesel. Today, there are nearly ten different fuel types to choose from. From petrol to plug-in hybrids, each one has benefits and drawbacks depending on usage.

But this can make choosing between petrol vs diesel vs hybrid even more of a challenge. Buying the wrong type could result in higher fuel costs, reduced practicality and even untimely repair bills. We're here to help you avoid this.

This expert-approved guide will highlight each fuel type, its pros and cons, and its best use cases. Scroll down to become an expert in minutes!

There are many benefits for each fuel type and also many drawbacks to consider. So, don’t rush your decision! Take your time to mull over this guide.

Petrol cars might catch your eye due to their lower price. Diesel cars might tempt those who make long-distance journeys or want better fuel economy. Hybrids are a great option if you’re not ready to go fully electric.

However, it’s not always this simple. Each fuel category has different car types, and we’ll discuss these below.

There are three types of hybrid cars. All use an electric battery and a combustion engine, but some significant differences exist. Plus, one is very similar to a diesel/petrol car.

Here’s everything you need to know about hybrids:

— These allow you to drive using your electric battery or standard fuel. The key difference here is that the battery in these cars is larger than that of other hybrids. They get plugged into an electric charging point for top-ups, but you must charge them regularly for the best experience.

— Mild hybrids are closest to diesel and petrol cars. These have small electric generators that run air-conditioning and start the car. Ultimately, the combustion engine will be the primary power source for movement.

— These cars run entirely on fuel or an electric battery. They can even use energy produced by braking to charge the battery, meaning you won’t have to plug into a charging point. These are also known as self-charging cars.

Weighing up whether or not to buy a hybrid car? Here’s how they measure up against petrol and diesel alternatives.

If you’re not ready for a hybrid car, your options are petrol and diesel cars. These run on the fuel you put in them and don’t require charging. No lifestyle changes here! 

We will explain the pros and cons of each type of fuel and hybrid below, but we’ll quickly compare petrol and diesel to help you decide.

These are the key petrol car strengths. But remember that petrol has a lower fuel efficiency than diesel and still leaves an environmental impact. Not ideal for your carbon footprint! 

Diesel cars are ideal if you’re a frequent long-distance traveller. However, they have a higher environmental impact and require expensive fuel.

Petrol vs Diesel vs Hybrid: Pros & cons of all fuel types

Choosing between petrol vs diesel vs hybrid isn’t easy. So, we’ve researched for you. See the advantages and disadvantages of each type below. 

Petrol is the one we're all familiar with and arguably the simplest of all in terms of mechanical complexity and cost.

In its basic form, petrol is burnt inside the engine to create mechanical power. The lack of various components compared to diesel (e.g. Diesel particulate filters, exhaust gas recirculation valves, dual mass flywheels and turbochargers) means fewer parts go wrong.

Petrol cars typically don't do as many miles to the gallon as diesel, though. Petrol is quite high in cost per kW compared to electric, although less so than diesel.

Although the ULEZs (Ultra Low Emission Zones) still permit most petrol cars without charge, there are plans to cease the manufacture of petrol and diesel cars in the 

Who do a mix of long and short journeys and don’t want to splurge. If you drive less than 15,000 miles per year, a petrol car will be cheaper than diesel. However, you could save more if most of your journeys are low-speed, short urban routes.

Diesel engine cars became popular in the early 2000s, mainly due to advancements in turbochargers and fueling technologies, allowing smaller diesel engines to compete (and exceed) petrol cars in fuel economy whilst still being powerful.

Economy figures upwards of 60 MPG can be seen from many common examples, even large vehicles such as VW Passats. Many people favour the power delivery of diesel and prefer driving them.

Since the 2000s, systems have been developed to help achieve these high performance and economy figures whilst lowering emissions. These include Diesel Particulate Filters (DPFs), Exhaust gas recirculation valves and high-performing turbos. 

However, diesels are still falling out of favour among car manufacturers. This is due to their higher emissions. More carcinogenic NOx (nitrogen-oxygen) is released by these cars, so many makers are avoiding them in order to meet green targets.

Who drive long journeys and have higher-than-average mileage. They’re also great for those who frequently tow caravans or trailers.

When they released the first generation Prius Hybrid, Toyota took the world by storm. It achieved extremely high fuel economy through petrol and electric power usage.

Since then, almost every auto manufacturer has included at least one hybrid in their range. From two-door sports cars and family saloons to pickup trucks and commercial vehicles. Clearly, they’re popular with the public, but what benefits do they offer? 

It’s important to note that many different types of hybrids exist, including parallel systems, mild hybrids, plug-in hybrids (PHEVs) and more. All of these can also be offered with a petrol or diesel engine.

 and motor system powered by the combustion engine and regenerative braking. The basic premise is that both engine and motor can power the wheels but are only used in the best conditions for each. 

When pulling away, the motor will do most of the work. Once up to speed, the petrol engine will directly drive the wheels the majority of the time. The car splits power from the engine and electric generator as and when required to keep the batteries topped up.

The benefit of this system is that fuel economy is greatly improved, both due to optimisation of the power types and regaining otherwise lost energy when braking.

Who want an improved fuel economy and aren’t ready to go 100% electric. Self-charging hybrids are great for low to medium-mileage drivers but are not ideal for long journeys.

PHEV cars use similar tech to self-charging hybrids but do not contain a generator to allow the combustion engine to top up the battery. Most still use regenerative braking because the already present electric motor performs this. 

In terms of user experience, they are different from conventional hybrids and internal combustion engine (ICE) cars in that you are required to fill them up with fossil fuel and charge them from the grid.

Many PHEV systems offer a mode whereby they operate on electric power only. With ranges usually sub 40 miles, it can be the perfect vehicle for someone with a sub-20-mile commute. No petrol would be consumed here - as long as it can be charged each night.

The petrol or diesel engine allows extended journeys without needing to plan for charging stops, which can be an issue with electric-only vehicles. However, this is not their ideal scenario, as once the battery power is depleted, the combustion engine must carry the extra weight of the empty batteries and motor.

Who mostly make short commutes. However, they can cover long drives when needed. This is also a good option if you’re ready to switch from fuel but don’t want a completely electric vehicle.

Learn more about hybrid batteries with our 

guide on hybrid battery replacement costs and FAQs.

Electric vehicles have existed for many years, but recent battery and motor technology advancements have allowed for much better range and performance figures.

Charge at home or a service station, and an electric motor converts the stored energy into propulsion. EVs are reasonably simple mechanically, but as their adoption is still not widespread, you may find few and far between independent repairers and spare parts will be costly.

Electric vehicles have the apparent advantage of not needing fossil fuels. An old argument was that energy is still generated using coal and oil, but in 2021, 

 of the energy produced in the UK was from renewable sources.

This makes EVs a much more environmentally friendly option. Another benefit is the lack of air pollution added to towns and cities, which will help with the quality of life in years to come.

They do have their downsides, though. Retail prices are still at least 30% higher than combustion-engined equivalents, but that is reducing yearly as manufacturing tech improves.

If the initial purchase price is not an issue, if you lease your cars, for example, then EVs' main benefit is their running cost. Even with 2022’s elevated energy prices, it will typically only cost £8 to fully charge a typical EV.

Assuming a range of approximately 250 miles, that makes fueling your car around 8x cheaper than a diesel doing 40 miles to the gallon. Over a yearly mileage of 15,000 miles could result in savings of up to £2,000.

Who are ready to go green. Electric cars require a larger upfront cost but don’t require expensive fuel. They’re also great for drivers who live near charging stations. If you don’t have a local charging network, an electric car might not be best for you.

Low emission zones are another factor to consider. While some drivers won’t come into contact with them, others will want to opt for ULEZ-exempt cars to avoid hefty fees.

London’s ULEZ zone is one of the largest and charges larger, more polluting cars £12.50 per day on entry. The aim is to reduce the emissions in the area.

Luckily, most petrol cars after 2005 are ULEZ exempt. If you want a diesel car, you’ll have to buy a car after September 2015. In contrast, all hybrids are exempt.

If your city doesn’t have a low-emission zone yet, it might have one in the works. Oxford, Birmingham, 

, and other UK cities are considering adding clean air zones in the future.

Petrol vs Diesel vs Hybrid: Which Is Best For Me?

It's no secret that garages can have a reputation as untrustworthy and if you pick the wrong one, you’ll end up with a 

This isn’t the case with most garages. Most are reputable businesses and supply excellent service, but how do you tell the good guys from the bad? 

We've put together a handy guide so you’re in the know. 

How good is the advisors’ knowledge? Have they explained everything in detail? When you’re being advised of the required work, you should be confident you know what you’re paying for. 

If you’re not, ask questions. What does that part do? Why does it need to be replaced? What are the consequences of not replacing it? 

A representative of a good, reputable garage will be well-trained and ready to answer any questions you have. 

Possibly the easiest thing you can do is check the garage’s reviews. Garage owners know that reviews are key to keeping customers walking through the door. 

Advice

Is Your DPF Blocked? 8 Warning Signs and How to Fix Them

4 signs your water pump is failing

How To Check if Your ABS Is Working

Petrol vs Diesel vs Hybrid: Which Is Best For Me?

Bumper’s guide to choosing a reputable garage

How often should I check my tyre pressure?

10 top tips on how to clean your car

How to check the fluid levels in your car