If you can smell exhaust inside the car
Open the windows, and don't sit in the car with the engine running. Fumes in the cabin can make people drowsy and unwell. If the engine light is flashing or the car has suddenly lost power, pull over somewhere safe and switch off, then have it looked at before you drive far.
Why do diesel filters clog in Adelaide?
A DPF cleans itself by burning off the soot it has caught. On a steady highway run that happens on its own. Otherwise the engine runs an active regeneration, raising the filter to around 600 °C, which RACQ says takes five to 25 minutes at about 80 km/h or more.
Short, stop-start trips stop that from starting or finishing, and RACQ calls them the most common cause of DPF trouble. Adelaide was long known as a twenty-minute city, which suits a petrol hatch better than a diesel ute that only does the school run and the shops.
RAA's suggestion is a weekly drive of 20 to 30 minutes at highway speed. A steady run up the Northern Expressway or down the Southern Expressway is the kind of driving it means. If the filter is left to clog, the car can drop into limp-home mode with the engine and DPF lights both on.
Exhaust trouble around Adelaide
After a trip on the tracks
The Oodnadatta Track is 614 km of unsealed road, and the Birdsville Track is a graded dirt road. Rocks, ruts and corrugations are hard on hangers, joints and heat shields. A new rattle or a louder note after a trip north is worth a look before it cracks a pipe.
Summer and dry grass
Exhaust parts run very hot, and a diesel in the middle of a regeneration runs hotter still. In an Adelaide summer, don't park a car that's just been driven on long, dry grass.
Where the rules sit
South Australia's exhaust and noise rules are the state's own, so check sa.gov.au for them. We'd never remove or gut a DPF anywhere: Queensland's regulation names DPF removal as an illegal modification, and EPA Victoria says it can't approve changes like that.
What the mechanic should check
- The stored fault codes, including any other fault that's stopping the DPF from regenerating.
- How full the filter is, and whether a forced regeneration is the right first step.
- If a forced regeneration is done, whether the engine oil needs changing too, because fuel can dilute it.
- Pipes, joints, hangers and heat shields, for leaks, cracks and anything loose.
- The catalytic converter if the engine has been misfiring, since misfires can damage it.
If it were our car
We'd deal with a DPF light early, while a highway run or a forced regeneration can still clear it. If the light keeps coming back, we'd ask the mechanic to find out why the filter isn't cleaning itself, rather than just clearing it again. And we wouldn't pay anyone to take it out.