Frequently asked DPF questions
Diesel Particulate Filters care and cleaning
Diesel engines are efficient, but they create sooty particulates in their exhaust that are bad for health. The DPF filters them out, but gradually gets full. Our cleaning service returns their full function.
Diesel Particulate Filters: FAQs
Diesel engines are efficient, but they create sooty particulates in their exhaust that are bad for health. Your Diesel Particulate Filter (DPF) removes the particulates by pushing exhaust gases through a maze of metal channels, collecting the sooty particulates.
Engine management systems are supposed to regenerate the filter unit when needed by applying high temperatures to the collected soot.
For various reasons this regeneration routine can fail (one of the main reasons is when the car is only used for short journeys, never getting fully up to temperature).
When the filter becomes clogged, exhaust flow is blocked. Eventually your engine management will apply a partial shut-down.
The filter is a closed unit, and expensive to replace. It can be cleaned, however, with the right tools and techniques.
If you have an engine management light on, the problem needs to be fixed – even if the light goes off from time to time. The light means the engine is not working properly.
Sometimes, engine management systems will put your car into “limp-home” mode after the fault is detected. That usually doesn’t change till the fault is cleared.
You may be able to get home, but until the problem is fixed your car is not really useable.
Most garages will prefer to simply replace the DPF unit, but this is expensive and rarely necessary.
Fortunately the unit can now be effectively cleaned without removal, at much lower cost.
You have the choice of buying a new DPF unit and getting it fitted (the most expensive option), or having your current unit cleaned.
Cleaning can be done by removing the unit and sending it off to be cleaned, or using our in-car cleaning service.
Of all three options, ours is the cheapest and quickest, especially when you consider the garage costs of removing and fitting a unit. Our service is also done while you wait, so you don’t have to be without your car for several days, or even weeks.
For an exact price for your vehicle, call us or fill in the enquiry form below.
There is a fourth option which disreputable garages may offer: they may advise you to have the DPF cut out. In the long run it is by far the most expensive option. Whilst it’s not illegal for them to do this IT IS 100% illegal for you to drive the vehicle once this has happened and if caught you can be liable for a fine upwards of £2000. Your car won’t pass its next MOT and will have little resale value.
There is a good reason for DPFs being a legal requirement – they remove diesel particulates (soot) from the exhaust. None of us wants to be breathing the sooty air that used to come from older diesel engines.
Modern engines with DPFs have actually brought about a very positive change in air quality levels, particularly in cities.
Yes, you do need it.
Some garages will offer and advise to have the DPF’s cut out and whilst it’s not illegal for them to do this IT IS 100% illegal for you to drive the vehicle once this has happened and if caught you can be liable for a fine upwards of £2000.
DPFs are a legal requirement – they remove diesel particulates (soot) from the exhaust. None of us wants to be breathing the sooty air that used to come from older diesel engines.
Modern engines with DPFs have actually brought about a very positive change in air quality levels, particularly in cities.
Your car will also fail its MOT if the DPF is not present, or if it is not working properly.
We provide a full, deep cleaning service for all Diesel Particulate Filters and Gasoline Particulate Filters where we aim to remove between 95-98% of the filter’s contents. The service we provide is the following:
– Pre-clean Health Check and Investigation: This allows our expert engineer to read all of the live data from your vehicle’s ECU. This will tell them how full the filter is in terms of percentage and the weight of soot in grams so we understand what we need to remove. Alongside this we are also checking all of the vehicle’s sensor, glow plugs and every other component involved with the DPF system to be certain the faults are not being caused by something else and that the clean will be successful
– Full Deep Clean of the DPF – Using our in-house manufactured cleaning solution our engineer will being the cleaning process which will take 45-60 mins to complete
– Post-clean Health Check and Investigation: We perform a post-clean health check on the vehicle, again to review the live data to ensure we have removed the contents of the DPF, reset any warning lights and that there are no other fault codes you need to be aware of. We will also, where possible, perform a short road test to ensure full power has been restored.
– Copies of both pre and post health checks: These will be emailed to you for your records
– 30-Day Aftercare Warranty: Designed to cover you for the next 30 days worth of journeys post-clean just in case you have any questions or concerns that we can assist you with.
We usually have next day appointments available, sometimes same day if you call early enough!
The cleaning process can take about 1.45-2.30 hours, if it is very blocked then worst case is 3 hours.
The benefits will be seen if you take care of the vehicle and take it out for long drives as recommended. The engineer that attends the clean will advise you on preventive measures.
The DPF is affected by how the vehicle is driven so we are not able to offer a warranty unfortunately. But we do offer a 28-day aftercare service in case anything DPF- related problems occur.
Yes, DPF Fixer engineers are available nationwide.
If it is a DPF problem then yes, we can help you fix it. For anything else that may need fixing we can advise you.
“Regeneration” means getting the DPF up to a high temperature (around 600c) to burn off the soot inside the DPF. It is triggered automatically when the car’s engine management system senses a problem. It can also be forced by a mechanic, but this carries the risk of causing cracks or internal damage in the DPF. If the engine’s automatic regeneration has failed to clear the blockage, forced regnerations rarely work unless physical cleaning is also done. Read more here.
Sometimes a garage will try to burn it off using forced regeneration but this doesn’t always work to clear the blockages if they are too severe. We specialise in DPF cleaning and can remove even the most stubborn blockages. We are the only company that has invested in manufacturing our own cleaning solution in order to offer you the guarantees we do.
Yes, after the clean of the DPF, the engineer will reset the relevant lights for this.
Yes, the clean can still be done.
Our engineer will explain how the DPF problem arose so you can avoid it happening again.
In the vast majority of cases, it is simply that the car is used for many short runs, so it never gets to proper operating temperature. So at least once a week it’s a good idea to let it properly stretch its legs.
There are also additives that can help, and our engineer will explain those.
We do have to warn you, though, that if the car is only used for short runs, it is only a matter of time before you see the same warning light appear.
Cars
Some accumulation of soot and ash in the DPF will begin whenever the vehicle is driven. Effects will be miminal at first, but gradually increase until the engine has to work noticeably harder to maintain power output – thus increasing DPF deterioration. Driving patterns, fuel quality, and general engine health all affect DPF service intervals – but for a sensible balance we recommend a professional DPF clean every 20,000 miles or 24 months. This greatly reduces the risk of costly repairs, keeps emissions in check, and maintains fuel efficiency.
LCVs
For LCVs – especially those performing short urban trips or operating under speed-limiting – optimum service periods are shorter, and the benefits of cleaning are often more noticeable.
HGVs
For HGVs, ash build-up can be a more significant issue than soot, since it is not cleared by regenerative heating. Proactive scheduled DPF cleaning is therefore an essential part of fleet management, and essential for maintaining engine efficiency.
We recommend professional cleaning after not more than the first 100,000 miles and then every 50,000 miles / 2000 hours thereafter.
Our engineers will always run a full diagnostics and health check to begin with to ensure the clean can be done. If there are any reasons that we can’t do the clean we would rearrange for another day after the other faults or problems have been fixed.
For 14 days after the clean we offer an aftercare service. If any lights come back on during this time we will revisit and do another clean of the vehicle for you.
Once we have started the actual cleaning process you don’t have to be there but we do need you to attend at the beginning and end. This is so the diagnostic test can be done, paperwork, payment and obviously to gain access to your vehicle to start.
The Booking fee when paid will secure the engineer, job date and job time of your choosing. The booking fee also covers the pre-clean vehicle health check and investigation where we confirm if your vehicle requires the clean or not. This report is also emailed to you for your records
No, this is not true. We will be able to clean your DPF if the vehicle is running ok. If however, the DPF is physically damaged you will need to replace the DPF.
The light will turn on if there is a DPF blockage.
If your vehicle can’t start or run properly this means there are other faults occurring and this means they will need to be fixed before we can perform a clean.
We are able to address the DPF faults and the blockages related to this. The dash lights will be then reset for this. Anything else is best to ask the engineer who performs the clean.