Exhaust smell inside the car?
Wind the windows down and pull over somewhere safe. Switch off, get out if you feel dizzy or unwell, and leave the car parked until it's been checked. If anyone is hurt or in danger, call 000.
Why Melbourne diesels block their filters
A diesel particulate filter (DPF) traps soot from the exhaust and burns it off every so often, which is called regeneration. RACQ says sustained highway driving does that by itself. Otherwise the engine computer adds a little fuel to heat the filter to around 600 degrees C, and that typically needs five to 25 minutes at about 80 km/h or more.
Stop-start driving can stop a regeneration starting or finishing, and RACQ names it as the most common cause of DPF trouble. A diesel that spends its week on short suburban trips and school runs is the textbook case.
Clearing a filter around Melbourne
A freeway run, outside peak hour
Melbourne has Australia's most extensive freeway network, so a regeneration run is rarely far away. The M80 Ring Road carries a 100 km/h limit off-peak for almost all of its 38.3 km. In peak hour the same trip typically takes 30 to 45 minutes instead of 25, and crawling won't clear a filter.
From the south-east
Peninsula Link runs 25 kilometres from the EastLink and Frankston Freeway interchange to the Moorooduc Highway, with no tolls. EastLink itself is tolled.
Go by your manual
Makers set their own speed and time, so follow your owner's manual. RACV says that if the check engine light is on too, another fault may be stopping the filter clearing. That's the time to stop trying and have it read.
EPA Victoria, smoke and noise
EPA Victoria says cars on the road must meet emissions standards, which cover noise too, and that using or selling one that doesn't is against the law. It also says it can't approve changes to an exhaust, giving diesel particulate filters as the example. Walk away from anyone offering to take a DPF out.
Anyone can report a Victorian-registered car that puts out smoke continuously for 10 seconds or more, and EPA Victoria advises the owner to have it checked and repaired. It also notes that steam on a cold morning can look like smoke, and that some diesels smoke a little going uphill as part of normal running.
A vehicle testing notice is a step up: the car has to pass a smoky or noisy vehicle test with an EPA-approved tester by the due date. Around Melbourne, the testers for cars are in Cranbourne, Epping, Hoppers Crossing, Moorabbin, Notting Hill, Ringwood, Seaford and Tullamarine. Miss the date and EPA Victoria can fine you or suspend the registration.
Got a vehicle testing notice?
Have the fault fixed first
The tester inspects the exhaust before the test and won't issue a certificate if it finds non-compliant parts or a defeat device. For cars built from 2005 on, the noise limit comes from Australian Design Rule 83/00. Get the repair done before you go.
Book any approved tester
Any of them will do, and a retest after a fail doesn't have to be with the same one.
Send the certificate in
A pass gets you a certificate of compliance. It goes to EPA Victoria online, by email or by post, before the due date on the notice.
What to get in writing before work starts
- The fault codes, and what the mechanic thinks caused the blockage.
- Which job it is: a forced regeneration, a clean or a new filter, plus an oil change if fuel has thinned the oil.
- For a blowing exhaust, which section, and whether it's repaired or replaced.
Where we'd start
For a DPF, we'd go to a mechanic who sees diesels every week, and ask what caused the blockage before paying to clear it. If the car's life is mostly suburban stop-start, we'd build a freeway run outside peak hour into the week. With an EPA notice, we'd get the repair done first and leave the test until the mechanic's happy.