Lockdown and DPF Filters

What to Do With a Badly Blocked DPF Filter

If your driving is restricted to short trips, make sure it isn’t slowly blocking your DPF filter — and more importantly, here’s what you can do to ensure your DPF filter doesn’t start causing you problems.

When a diesel vehicle is restricted to short trips, lots of stop-start, and city driving, the DPF filter is supposed to collect all the excessive soot particles and burn them off cleanly. But more often than not, the DPF filter slowly starts to block up. Unfortunately, you often won’t know there’s a problem until it’s far too late.

If your diesel car does a lot of city work, it could do with decarbonising — especially if it is fitted with a diesel particulate filter (DPF).

Short-Trip Driving Creating DPF Worries?

Normally, a good highway run is what helps keep these DPF filters working properly. But there’s an even better, more effective way to do it — and you can do it easily from home. All you need is a small bottle of FTC Decarbonizer.

The easiest and most effective way to clean and maintain your DPF filter is to use FTC Decarbonizer. For the science behind it, see our guide on how FTC Decarbonizer works.

How to Clean a Heavily Blocked DPF Filter

For vehicles with a heavily blocked DPF filter, this process can be followed:

Add four times the standard dose of FTC (1 litre to 400 litres of diesel).
The idea is to maintain the engine in the higher rev band for extended periods, as this is when decarbonising is most effective. Be kind to the engine: let it warm up a bit, then progressively increase revs, step by step, until about ¾ of the way to redline.
You can vary the revs a bit, give it a few sharp bursts, or do it for 10 minutes at a time — a few times a day, or several times a week.
When possible, take the vehicle for a minimum 45-minute drive.

Of course, if you’ve been using FTC for a good while, your engine should have very little carbon internally.

Another DPF Maintenance Tip From CEM:

A lot of DPF problems are blamed on a faulty “5th injector” — the extra injector that feeds diesel upstream of your DPF during regens. In almost all cases it’s not faulty; it’s fouled internally, causing it to leak and continually dribble fuel into the exhaust stream. This is a big cause of white smoke!

FTC Decarbonizer works during combustion, and since combustion can’t happen inside the injector, you need a good, effective injector cleaner such as CRD Fuel Enhancer to clean it up. Keep in mind that the extra injector only passes fuel for a very short time compared to the main injectors, so inferior injector cleaners won’t cut it.