The makers respond…

Diesel vehicles require at least one ‘hot’ run every week at free eeway speeds, under load for at least 20 minutes

The cost to replace a diesel particulate filter on a Hyundai i30 can be u e up to one-third of the new car price – $7000 for the part plus a big lick of of labour.

On a Holden Colorado it is $730, a price that also includes a new catalytic converter. A factor of 10 variance for essentially the same bit o bit of kit?

Hyundai is by no means the high point for DPF pricing. The disparity is one o on ne of many lurking in the fine print of the automotive industry’s spare par sarts and service schedules. But it takes a deep and determined dive to unncover them.

Wheels asked the manufacturers some basic questions ranging from official service intervals to how they deal with carbonised intake systems as well as the slated life and replacement price of diesel systems particulate filters – an essential piece of emissions control equipment.

Some didn’t respond at all after several attempts. Which is why you don't see Mazda and Mitsubishi listed here. Some provided basic service t s handbook pages but no pricing. Nearly all ignored the intake side carbon handb bo sludge issue and blocked Exhaust Gas Recirculation (EGR) systems.

Here’s the round up. You be the judge. Here’

Depending on the model, DPF costs range from $4800 to $6000 plus labour. Audi claims the DPF “shouldn’t need cleaning or changing during the normal life of the car.”No response on intake side carbon build up or blocked EGRs.

Urban battle

The major car brands continue to insist that early failures of their diesel particulate filters are a form of owner abuse. Many are then refusing warranty claims on DPFs.

They justifiably claim diesel vehicles require at least one ‘hot’ run every week at freeway speeds, under load for at least 20 minutes, to instigate what they call a passive regeneration within the blast furnace of e of the DPF. Too many owners, ers they say, don’t read their ir owner’s manuals and stop/ t start, short, cold runs in an an urban environment don’t get ’t get the filters up to operating temperature.

Supporting that claim are case studies Wheels has seen of citybased European marques with low kilometres but filters blocked by 85 percent.

One BMW customer drove ove from Bondi to Maroubra in Sydney every day (a distance of maybe 15km)m) and presented with a blocked DPF at 60,000km.

On the flip side, service c centres are also seeing failed faile DPFs on country cars that at routinely log plenty of long,gong, hot runs.

In what may be a pointer toer t the future, only one company, mpan Subaru, tells customers their diesel Forester and Outback models are not well suited to prolonged urban use.

The bottom line here is if you do the school run and the shopping, rarely leaving the city limits, you are much better off with a petrol engine. It will save money too, given the hefty upfront price premiums charged for diesel models and the ongoing maintenance issues. ongoing main nance is

Dry run

The sulphur content of Australian diesel fuel has fallen from 500 parts per million in 2002 to 10ppm today, another tailpipe-focused outcome. Diesel now has five times less sulphur content than Australian petrol, although new regs are imminent to reduce those levels to parity. So what? Sulphur combines with other elements to produce a lubricating effect in engines.

“The moment the sulphur “T e mome the su ur came out we went through two years of replacing injectors and getting pumps overhauled,” says Frank Spiteri. Indeed, injector and pump failures showed a spike as sulphur levels fell but the consensus now is that the problem has been largely solved with new component countermeasures.

For the record, a diesel pump costs around $2500 and replacing a set of injectors can tip $3000 with labour and an ti ith coding costs.

No pricing pr g provide ided al althou ough independent s independent servic ice agents showed Wheels invoices for an X5 DPF at $5126 plus labour.

BMW says, “our particulate filters are maintenance free and are designed to last as long as the vehicle.”

No response on carbon build up.

Prices range from $2200 on a Ranger to $2600 on a Mondeo, plus labour. Ford says its DPFs are designed to last the life of the vehicle and “should therefore be of no concern to the new vehicle buyer – or the second or third, for that matter.”

No response on EGR carbon build up.

Fiat Chrysler Australia quotes “in excess of 150,000km” as the expected service life of its particulate filters – albeit with the usual riders from the warranty department.

“Poor fuel or oil will very quickly contaminate a DPF.”

A replacement for the company’s Alfa Romeo Giulia is priced at $9602. With labour and coding costs the retail bill could be expected to comfortably top $12,000.

The Jeep Grand Cherokee filter is a $5409 item and the Compass $7693. The company has no service recommendation for any decarb of the inlet system/EGR.

Afrankresponse citing servicelifefor the ponse DPF as “the lifetime of the vehicle” and that regular intake decarbonising procedures are unnecessary.

Replacement filter prices range from $5683 for a Tucson to $6991 for a new i30 or i40. Plus labour, of course.

Parts-only replacement cost for DPFs range from $4000 to $6500 and are a claimed “lifetime” fitment. On the carbon issue the response was forthright.

“Given the location of these components and the complexity of reaching them mechanically or with chemicals it is not only unnecessary but also cost prohibitive.”

While acknowledging there are no scheduled servicing parameters for “decarbonizing or cleaning Exhaust Gas Recirculation (EGR) and intake components” the JLR says the emission system carries out “strict monitoring and will alert the driver to seek retailer attention should any compromise to performance occur.”

The company response was that it had “never sold a replacement” (not surprising as they are extremely expensive.) Kia said “the general view is that if they are driven as recommended in the owner’s manual then they will outlast the car.”

No pricing and no response on carbon build up.