DPF Cleaning & Replacement
A DPF light can be such a stressful light for a car owner to see. It exists only on diesel cars and the repair must be handled by a garage that understands the system, how it works and how issues can be resolved. That’s where we come in, our mechanics are highly trained and experienced in DPF cleaning, repair and replacement. Just give us a call and have a chat with one of our experts, they will talk you through your issue and get you booked in for an inspection
What is a DPF?
First to understand why a DPF fails, it’s important to understand how the system works. It stands for diesel particulate filter and it replaces a system in your exhaust called a catalytic convertor. It does the same job, but works in a slightly different way. The system cleans the exhaust gasses that your car produces so that the end result is a low carbon, environmentally friendly output. This allows your diesel cars to have much cheaper tax than they had many years ago and be a lot more efficient.
Sounds like a good system doesn’t it? Well it is and its been used in large wagons since the mid 80s. However, its drawback comes from the way in which it operates over long term. So in order to clean the gasses, it doesn’t just filter them, it physically traps the fumes. This results in the system obviously accumulating particulates in the filter and this needs cleaning very regularly. It’s this cleaning process that causes 99% of issues with your DPF. The cleaning process is also called regeneration.
What is DPF Regeneration?
DPF regeneration is the cleaning process a DPF has to undertake when it’s becoming full of the particulates your car produces during operation. The system uses a 3 pronged approach to regeneration.
- DPF Pressure Sensor: This senses the pressure in your exhaust and measures how full the system is. Then a pulse is sent to the engine to start the regeneration process.
- A Fluid: This fluid is either an additive attached to the car, or diesel directly from your tank. This is injected into the DPF to help burn the particulates out of the filter. The fuel/fluid basically helps the carbon melt slightly and allow it to burn off at lower temperatures.
- Your Engine: As part of the regeneration process, the burnt off carbon needs to be pushed out of the system. This is only done at a certain pressure and comes from your engine running at a speed of 2,000 rpm and upwards.
The process takes a little over 15 minutes on most cars however, the failure comes at some point during the process. The sensor, that detects the levels in the system, can fail, this means the system will not generate and your DPF will continue collecting carbon until the pressure is so high that it causes damage to your engine. The fuel/fluid may also fail to enter the system, causing similar damage. Or the most common cause of DPF failure, is the engine not running for long enough.
As the carbon needs temperature to be burnt off and then enough pressure to push it out of the exhaust your car must be running at full temperature and engine speed of 2000 rpm. You also must have at least a quarter of a tank of fuel to ensure the regeneration process is successful. This is where many issues come in, if you’re not driving your car along the motorway for long periods of time, you will run into this issue. Unfortunately there is no real way around it apart from physically running your car along the motorway every so often.
How Do I Know if my DPF is Needs a Regeneration?
Fortunately enough, cars are built with a lot of failsafe features nowadays. This is not a guarantee that further damage won’t happen but it gives you indications early enough that there is a problem and it needs to be looked at. A warning light on the dashboard may just be an engine management light, an exhaust looking light (DPF Light) or wording on the computer that tells you DPF regeneration required. It’s at this point it’s time to take your car up the motorway and see if that solves your issue.
However, if your car has gone into failsafe mode, where your speed is reduced by the computer (Also known as limp home mode), then it’s time to get your car into a garage for some inspection as the system may need a manual cleaning or replacement.
How Do We Clean a DPF?
Here at Childwall Fiveways Auto Centre, we have invested in the latest technology to help clean your DPF and make it almost like new. The system we use depends on your make and model, however, our cleaning process involves using a fluid much stronger than your car has as well as a high pressure system to help flush the carbon from the DPF. Depending on the level of carbons in your system, this can take more than 1 attempt to fully clean the system.
Once the system is clean, we will then also use our diagnostic equipment to ensure your system is cleaned enough to regenerate on it’s own. Only when our mechanics are happy with this, is when you will have your car back as good as new. However, it’s very important to note that if your car continues to fill up with carbon, it needs to be used more on longer journeys. Or, it could indicate much bigger problems on the horizon for your car.
Sometimes, when the DPF is so full, it starts to break down inside, or the carbon is so compact it’s impossible to clean. In this case, we recommend a replacement. However, replacement systems can be extremely expensive. With costs from £300 upwards alone for the part, you could be in for an expensive run.
How do I Prevent DPF Failures
- Drive Longer Distances More Often – This is key as your diesel car is built to drive longer distances and during these drives your regeneration will take place when it needs to.
- Ensure You Have Fuel – Keeping your tank above 1/4 of a tank will mean the computer will not fail to start the regeneration process.
- Use Better Fuels – Buying your diesel from certain sources can be of lower standard than others. Particularly if your car uses diesel as the fluid for its regeneration. Poor standard of fuels can reduce the efficiency of regeneration and produce more carbon while it’s running. Making it a double edged source for your DPF problems.
These are extremely basic things will keep your DPF in better condition for a lot longer and potentially save you large bills by asking a DPF garage to do the cleaning for you.
Can I remove my DPF?
Many clients ask us “Can I just remove my DPF?” The answer is categorically NO. Although it is not illegal to remove your cars DPF, it is illegal to drive your car without it installed and you will also fail your next MOT if you have removed your DPF.
What If I’m Having DPF Problems Today?
If you are having DPF problems today with your car, it can be a frustrating process to find a garage that understands the system and can apply a repair. Always leave your DPF repair, cleaning or replacement to a garage that is confident and with the right equipment.
Here in Liverpool, we consider ourselves a specialist DPF cleaning garage. Our mechanics will solve all your DPF related issues and understand that it’s different on every single car. So if you’re having a dpf issue in Liverpool, then drop us a line. Our friendly team will be happy to help you.