Automotive emissions are a sensitive topic nowadays, making it all the more important to make sure that your car is up to code. The last thing you want is for your vehicle to fail an MOT inspection, forcing you to spend huge sums of money trying to get it to a point where it isn’t a smog-spewing menace.
This is a struggle which owners of diesel-powered cars are likely to know all too well. There are certainly many advantages to diesel-powered vehicles, but there is no denying that this is one area in which they struggle. That’s also why recent years have seen diesel-powered vehicles incorporate diesel particulate filters to help ensure that they run more smoothly, cleanly, safely, and efficiently.
If your DPF runs into trouble, therefore, you’ll want to troubleshoot the issue, and fast.
For those not in the know, your DPF works to trap diesel gas and filter the particulates it produces as cleanly and efficiently as possible. The soot particulates which result after the gas is burned must then be recycled out so the process can begin again.
Your DPF should last a good while, with the best models able to continue filtering at 10,000 miles’ worth of service. That said, when servicing the DPF itself, you’ll want to take care to use diesel-approved oils, as non-standard options can clog the filter. Clogging is already a common issue with DPFs, as discussed below, so you’ll want to mitigate this as much as possible.
Before you can understand how to fix DPF problems, you need to be able to identify them. Some of the telltale warning signs of a DPF problem are as follows:
- Reduced fuel efficiency
- Sluggish throttle
- Difficulty starting your vehicle
- Foul smell emanating from the DPF
Causes of DPF Problems
some of the most common causes of DPF issues include the following:
- Short drives, which can deprive your engine of enough time to heat up, which is necessary to operate at optimum efficiency, including burning off soot
- Your DPF starting to wear out after 10,000 miles of usage
- Clogged valves
- Too much fuel, which can exacerbate clogging
- Problems with the fuel injectors
- Using the wrong type of oil
- Oil leaks
- Issues with your car’s turbo feature
Fixing Blockage and Other Issues
As mentioned above, one of the most common issues with DPF is clogging. On the one hand, clogging is definitely a huge concern, and something which, if left unchecked, can severely damage your DPF and cause greater problems for your vehicle. Thankfully, however, as long as you recognise and address clogging early on, you should be able to avoid these issues.
There are several ways of dealing with a clogged DPF filter, the most obvious of which is to get it cleaned. That said, it will already be inspected as part of an MOT checkup, and getting it cleaned or in between checks or outright replaced can be costly.
Thankfully, there are many simple ways of cleaning it out yourself, with none simpler than simply driving your vehicle. Periods of disuse can cause soot and oil to collect and clog the filter. The same is true of not driving fast enough to make your filter become hot enough to burn off the soot.
If you have the need for speed, unleashing it in a responsible law-abiding fashion can actually help you clear out your DPF.
You’ll also want to check your car’s EGR valve. If this is damaged, fixing your DPF will be even more difficult. Faulty EGR valves cause an increase in crankcase vapour, which in turn can lead to further DPF problems. EGR valves sticking is a relatively common cause of DPF issues, so if this is the case, all you need to do is loosen it and reset its position
You’ll also want to make sure that you are using diesel or premium fuel. Using a lesser fuel will rob your vehicle of much of its extra power. What’s more, diesel and premium fuels contain additives which are specifically designed to help your DPF burn off these extra particulates. With other fuel sources that lack those protections, therefore, the risk of clogging increases.
Active and Passive Regeneration
You cannot do without a DPF. It has been part of the MOT’s vehicle check guidelines since 2014. If it is clogged or suffering from other issues, therefore, you’ll have to find a way to fix it. The easiest way to do that is by making sure that the unit can “regenerate” itself when it starts to fill with soot.
There are two methods for doing so – actively and passively.
Active regeneration allows you to take matters into your own hands and regenerate your DPF system on your own. This involves injecting even more fuel into your ECU. You can do this by engaging your car’s regeneration cycle, which you can typically trigger automatically by driving at elevated speeds for short bursts. Most cars with diesel engines have a warning light indicating blockage, which will turn off once you have successfully cleared it via active regeneration while driving.
Passive regeneration, meanwhile, takes place when your car is operating at speeds which allow the vehicle to burn off that soot naturally. As mentioned above, long journeys which allow your DPF to reach higher temperatures are a good example of passive regeneration at work.
For this reason, you’ll want to make sure that, if you buy a car with a DPF system, you intend to use it regularly. Plan on driving it at least once a week for at least half an hour to an hour. If you cannot commit to driving it for longer than that or at more frequent intervals, the DPF will likely encounter issues. Besides, given the expenses associated with diesel vehicles, buying one that will be used so infrequently may not be a wise move economically.
By knowing the ins and outs of how to clear and fix your DPF system, you can avoid and address issues and keep it humming along as cleanly and efficiently as possible.
Last Updated On: April 29, 2020.