10 tips to make your diesel car's particulate filter last longer

Particulate filters work as “traps” that store the particles produced during combustion, to remove them later in a filter regeneration process that requires high temperatures, on the order of 500 degrees Celsius.

To do this, the engine management system injects an “extra” amount of fuel when necessary, so that the temperature of the exhaust gases rises. Another of the engine’s tricks for getting rid of particles is the use of the Adblue additive, which can lower the temperature needed for those particles to burn. Here is a complete guide to AdBlue, with maintenance tips and prices.

Well, knowing all this, one might think that in winter, with low temperatures, your car’s particulate filter will suffer more than usual and be more exposed to possible failures. Indeed, low temperatures can be the final blow to your car’s particulate filter, if it is not in good condition. To avoid problems with the particulate filter, not only in winter but at any time of the year, here are some tips that may be very useful.

1.- Maintenance: always in top condition

The car must be kept in good condition. You will avoid many headaches if you comply with the scheduled servicing, whether by mileage or by time. For example, in many new cars when the warning light indicating that the car must go to the workshop for an oil change comes on, the system may decide not to trigger high-temperature filter regeneration phases to protect the engine until the oil is replaced.

2.- Oil for engines with DPF

We come to one of the key aspects for the engine: you must use the correct, good-quality oil. Sulphated ash is a real “poison” for the particulate filter, which is why manufacturers recommend low-ash oils for cars with a particulate filter. So you know: check your car’s manual and make sure you use the right oil. Here you can see some of the most dangerous failures that can be caused by not using the right oil, and the particulate filter is among them.

3.- Levels: keep an eye on the oil

We continue with the oil. Checking the level frequently is essential. In many diesel cars, precisely because of those “post-injections” of diesel to raise the temperature and regenerate the filter, the engine oil sometimes gets mixed with fuel, causing the level to rise. If your car’s oil level suddenly exceeds the maximum, it is a sign that there may be a problem in the fuel injection system or in the particulate filter. Also, remember that you should never add oil above the maximum level indicated by the dipstick.

4.- Don’t fill the fuel tank to the top

Do not try to overfill the fuel tank. Many users wait for the foam generated by the diesel entering the tank to subside and for the air to be expelled, and then insist several times with the pump nozzle after the automatic cut-offs the pump makes when it detects the tank is full. It is true that, this way, you can end up putting in more fuel, sometimes even more than a litre extra, depending on the car and the pressure at which the pump delivers the fuel. But on some cars this can cause the Adblue additive system (although the additive has its own separate tank) to malfunction.

5.- Adblue: your particulate filter’s best ally

And since we are on the subject of additives, be careful with Adblue. If you choose to top up the Adblue tank yourself instead of going to the dealership, use original additive and check that the one you are buying is suitable for your car. It has become highly standardised, but the different generations of AdBlue are not always compatible or valid for every car.

6.- Check the maintenance manual

For this last reason, it is especially important that you read your car’s maintenance manual, paying particular attention to everything related to the particulate filter, how it works, what happens if your car runs out of AdBlue, what type of additive to use and how often to refill it… Some manufacturers even give specific driving advice aimed at helping to clean the particulate filter.

7.- Dashboard warning lights: an early warning

Pay attention to the warning lights on the instrument cluster. Find out what each light means: in some cars the DPF light directly indicates a fault. In others, a flashing light before it stays on may indicate that the filter is about to clog, and in this case we can “help” the regeneration with our driving style.

8.- Encourage filter regeneration: drive “spiritedly”

From time to time, especially if you do a lot of city driving, give the engine some “life”, as long as it is already at operating temperature and you are keeping the oil and its level under control. A stretch of motorway of about 15 or 20 minutes at a steady speed, with the engine revving high in an intermediate gear (try to keep it between 2,000 and 3,000 rpm), will help the filter regenerate.

9.- Consider using premium diesel in winter

Use “premium” fuel. Yes, in winter, spending a few euros more on higher-quality fuel can help: the cleaner combustion of this premium diesel produces fewer particles, which helps keep the filter in good condition and means it needs to regenerate less often.

10.- Don’t delay your visit to the workshop

Don’t ignore a possible problem. A clogged filter that does not regenerate keeps filling with ash, harming the operation of the rest of the engine systems, and the final repair bill can rise exponentially.