The nightmare of the modern diesel engine has a short three-letter name - DPF. While in the summer the particulate filter quietly does its job, purifying the exhaust gases from soot, the onset of frost turns this component into a real battlefield. Winter is the biggest test for the exhaust system, and the reasons for this lie in the simple physics of low temperatures.
The main stumbling block is the temperature regime. In order for the filter to self-clean (a process known as regeneration), an extremely high temperature of the exhaust gases is required. On frosty days, however, the engine warms up painfully slowly. If we add to this the short city commutes, hanging in traffic jams and frequent cold starts, it turns out that the system almost never reaches the operating temperature needed to burn off the accumulated particles.
There are two types of regeneration, but both suffer from the cold. Passive regeneration requires long driving outside the city at a constant speed - a luxury that few people can afford in winter everyday life. Active regeneration is controlled by electronics, which injects additional fuel to "bake" the filter. Alas, at this very moment we often arrive at our destination and turn off the engine, interrupting the cycle. The result? Soot accumulates like snow in front of an uncleaned front door, until the filter literally suffocates.
The symptoms of impending trouble are easily recognizable: the car becomes sluggish, fuel consumption jumps inexplicably, and the indicator on the dashboard starts to glow with threatening persistence. If you ignore these signs, the car will inevitably go into emergency mode, and the service bill will reach alarming parameters.
To avoid this, prevention is key. Here are a few golden rules: at least once a week, "walk" the diesel on a long road for 20-30 minutes to allow the system to breathe. Forget about endless spot heating - this only accelerates soot clogging. Be sure to use ACEA C class engine oils, specially developed for cars with filters, and do not underestimate high-quality fuel additives that help soot burn at lower temperatures.