The WhoCanFIxMyCar guide to Diesel Particulate Filter (DPF) cleaning
How much does it cost to clean a DPF?
What is a Diesel Particulate Filter (DPF)?
A diesel particulate Filter (DPF) is fitted to the exhaust system of diesel cars. It stops harmful particles from entering the atmosphere following the combustion of fuel within the engine.
The cell plugs inside the DPF prevent the soot and and ash particles from escaping and becoming a hazard. However, over time, the cell plugs become clogged and lose effectiveness.
Why should I get my DPF cleaned?
There is a genuine and direct risk to the health of the public if a DPF is not filtering out dangerous particles. However, the risks are not just limited to air pollution.
If your DPF becomes blocked, your car may suffer damage to its turbo, and if that happens, it may suddenly revert to limp mode which restricts the car to a certain speed.
How is a DPF cleaned?
Fortunately, diesel particulate matter burns when temperatures above 600 degrees are attained during a process called ‘regeneration’.
Regeneration is triggered by an onboard computer when it detects the DPF becoming clogged; this is an automatic function that your car will carry out itself.
However, regeneration often fails and the only way to clear the DPF is by having it cleaned. A DPF cleaning expert will use one of three methods: ultrasonic cleaning, kiln cleaning or pressure pulse cleaning.
Ultrasonic cleaning is recommended when there is only a moderate level of blockage. It involves placing the DPF into a specialist chemical bath where it will be go through a sequence of ultrasonic treatments.
A kiln clean is very straightforward as the entire part is simply put into a kiln and heated up to 900 degrees. The heat literally burns away the soot present in the DPF.
Pressure Pulse Clean
During a pressure pulse clean, the DPF is flushed with specialist fluid and pressure loaded to identify which cells are blocked in order to be able to clear them out.
Though you can get a new DPF fitted if your current one is full of soot, it is not the most environmentally friendly or economical decision you can make.
Industry figures show that up to 70% of DPFs are unnecessarily scrapped, which means a huge number of drivers are paying more money for replacements when a cleaning service will restore the part to perfect working condition 96% of the time. A clean will only ever take 24 hours using the techniques listed above, whereas getting a new DPF fitted will require a car to be off the road for longer.
To help diagnose the specific problem, we’ve come up with a handy guide.
Issues with Glow Plugs
If white smoke is being produced and the engine fails to start, the glow plugs may be the root cause of the problem. Lubricating the piston rings may resolve the issue.
Failed EGR Valve
Simply clean the valve using a carb cleaner solution and the warning light may disappear.
Temperature / Pressure sensor problem
There is nothing you can do if there is a problem with the sensors in your car, you will need to take it to a garage for repair.
Exhaust / Injection system
If you see unusual smoke or if you can smell sulfur, try cleaning the immediate area when the exhaust is cool.
The clogged diesel particulate filter may be causing this issue, though driving on a motorway for around 20 minutes may resolve the problem through the process of regeneration.
Your turbo may fail as a result of using the wrong engine oil. You might expect the engine oil light to come on for this fault but there is also a strong chance that the diesel particulate filter light will also come on.
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