Common faults below

Holden Engine Carbon Cleaning

What we see most on Holden engines, what causes it, and which clean fixes it. Every job starts with a scan and a quote at our Kings Park workshop.

Free scanbefore any work
Kings ParkSydney workshop
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Which Holden do you have?

Every Holden on the road now is a used car, and most are past the age where a dealer would have looked after them. That changes what these pages are for — nobody is under warranty, and the question is usually whether a tired car is worth keeping.

If you have a Colorado or Trailblazer, it is the 2.8-litre Duramax diesel, and we see plenty of those. The intake manifold and its runner control are the weak point, and P12AF is the code that brings most of them in.

If you have a Commodore, later cars used direct-injection petrol engines, so intake valve carbon applies to those in the same way it does to any modern petrol engine.

We scan first and tell you what it will cost before we start. On an older car we will also tell you when something is not worth doing.

Common Holden carbon problems

What we see

If you drive a petrol Holden

Petrol

Intake Valve Carbon on the Petrol Models

Later Holden petrol engines inject fuel straight into the cylinder, so nothing washes the back of the intake valves.
Oil vapour from the breather bakes onto the hot valve and hardens.
On a car of this age the deposits have had a long time to build.

Lumpy idle, worst from cold.
Hesitation off the line and softer throttle response.
Misfire codes (P0300–P0306) with the ignition side checking out fine.

Walnut blasting once deposits have hardened — the intake comes off and each port is cleaned mechanically.
A hydrogen carbon clean will keep on top of it if the crust has not formed yet.

Fixed by

Walnut Blasting

Quoted after the free scan

See the service →

If you drive a diesel Holden

Diesel

Intake Manifold and Runner Control on the 2.8

The EGR valve feeds sooty exhaust gas into the intake, where it mixes with oil mist from the crankcase breather.
That mixture leaves an oily film through the manifold that hardens into a deposit and narrows the runners.
As it builds, the intake manifold runner control flap can no longer move freely and eventually sticks — which is what stores P12AF.

P12AF, often with P042F or EGR flow codes alongside.
Flat throttle response, worst from low revs.
Black smoke under acceleration and rough idle.
A ute that feels noticeably slower loaded than it used to.

We clean the EGR circuit and the intake manifold so the flap moves freely and the airway is clear.
If the flap or its linkage has already broken rather than stuck, cleaning will not fix it — we will tell you that instead of charging you for a clean that cannot work.

Fixed by

EGR & Intake Manifold Cleaning

Quoted after the free scan

See the service →

Diesel

Particulate Filter Blockage

A regeneration needs a sustained run to burn the soot out. Short trips and low-speed driving never provide one.
A restricted intake or a poor injector loads the filter faster than normal use would.
Every interrupted regeneration leaves the filter fuller, and high backpressure puts extra strain on the turbo.

DPF light, then reduced power and limp mode.
Fuel consumption up and a hot smell after parking.
Gaps between warnings getting shorter.
Codes in the P2002 and P2452–P2463 range.

Where we can, we clean the filter on the vehicle — nothing removed, cut open or replaced. If it has to come off, it gets a three-stage clean and new gaskets, quoted first.
We check the intake and fuel sides in the same visit, because on these engines the filter is usually the symptom rather than the fault.
Nothing is deleted. A vehicle without its emissions equipment is not roadworthy in New South Wales.

Fixed by

DPF Cleaning

From $715

See the service →

Diesel

Injector Fouling and Hard Starting

Deposits on the injector tips spoil the spray pattern, so diesel arrives as droplets rather than a fine mist.
Poor combustion makes more soot, which loads the filter faster.
Age and fuel quality both play a part on cars of this vintage.

Hard starting from cold.
Rattly or uneven idle.
Smoke on start-up and worse economy.
Fuel rail pressure codes (P0087, P0088, P008A).

We clean the whole fuel system on the vehicle with the engine running — injectors, pump and rail — nothing removed or sent away for bench testing.
On an older ute this is often the cheapest thing that makes a real difference.

Fixed by

Diesel Injector Cleaning

Quoted after the free scan

See the service →

If you drive a hybrid Holden

Applies to any Holden

Any Holden

Keeping a Holden Going Without a Dealer

There is no Holden dealer network any more, so these cars get passed between workshops and problems tend to get treated one code at a time.
On a car that has done real distance, the intake, the filter and the fuel side are all dirty together.
Fixing one and leaving the others just moves the problem along, which is why the light keeps coming back.

The same code returning after being cleared.
A car that has been to several workshops with nothing sticking.
Several unrelated-looking faults appearing over a short period.

A full engine carbon clean treats the intake and exhaust sides together, which is the right scope when the whole engine is dirty rather than one part.
We scan first, tell you what we find, and give you the cost before anything starts — including when the honest answer is that the car is not worth the spend.

Fixed by

Full Engine Carbon Clean

From $715

See the service →

Any Holden

Short Trips and Stop-Start

A Holden doing short suburban runs spends most of its time below the temperature at which the engine stays clean.
Soft carbon settles on valves, piston crowns and chamber walls before it can burn off.
On a car that is already old, this is what tips it from tired into faulty.

A car that has always been “a bit tired” and has quietly got worse each year.
Idle that hunts on a cold morning.
Nothing stored on a scan — which is usually why nobody has looked at it.

A hydrogen carbon clean is the maintenance step for this. Nothing comes apart, and it works on soft carbon before it hardens.
On an older car this is the low-cost option that tells you whether the car still has life in it.

Fixed by

Hydrogen Carbon Clean

$275

See the service →

Watch us clean a Holden

Real jobs from our Kings Park workshop — the same work we would do on yours.

Watch Holden Captiva: on-car DPF clean on YouTube
Holden Captiva: on-car DPF clean
Watch Holden Colorado Intake Cleaning on YouTube
Holden Colorado Intake Cleaning

Keeping your Holden clean

Prevention

To keep a Colorado or Trailblazer clean, give the 2.8 Duramax diesel a steady run of about half an hour every week, or an hour every fortnight, as Nas advises. Short trips and low-speed driving never let its particulate filter burn the soot out. In the intake, EGR soot and breather oil mist harden until the runner control flap sticks. For a Holden doing short runs, a hydrogen carbon clean is the maintenance step. Later direct-injection Commodores build carbon on the intake valves instead.

If your 2.8 has gone flat from low revs or blows black smoke under acceleration, book a time at our Kings Park workshop. We scan it free first, tell you what it needs, and quote before any work starts. That may be an EGR and intake clean, with an on-car DPF clean if the filter has loaded up too.

Genuine and honest man, Nas is a great mechanic and stuck to his word fixing my diesel EGR valve, removed the dirt and fixed the engine light. Reliable and honest service.

Belmir Hrnjadovic, Diesel · Google review

Nasir saved us a world of pain by doing an emergency DPF cleaning on our Mazda 6 onsite. His service was professional and effective. His method of doing a 'chemical clean' on the DPF onsite without the labour of removing it is something we had not heard of before but seems to be proven now with the way the car is driving (it's like night and day compared to a few hrs ago and the turbo has returned). We have been aware of issues with the DPF on our vehicle for a while and have spent an arm and leg to have it removed to be cleaned before. Our car has high Kms on it so we know this clean is likely just a temporary solution but Nasir was kind enough to help us really last minute and has helped us to get to our holiday destination comfortably knowing we've potentially avoided massive fees in towing (and likely much higher fees from anyone else who would have removed the DPF) so I'm stoked! 😊 thankyou.

Rebecka Odlander, Mazda 6 · Google review

Before any engine work on your Holden, search your VIN on the government vehicle recalls site. Recall repairs are free, so check there first.

Act before limp mode. On the 2.8, shorter gaps between DPF light warnings are a sign the filter is blocking. Left alone, it ends in reduced power and limp mode, and the backpressure strains the turbo.
Don’t put up with hard cold starts. Fouled injector tips spray droplets instead of a fine mist. That makes more soot, which loads the filter faster.
Book in when the cold idle hunts. There may be no code stored, which is usually why nobody has looked. Caught while it is soft, the carbon can be cleaned before it hardens.

Book your Holden in

Get a free quote

Tell us the model, the kilometres and what it is doing. We will scan it and tell you which clean it needs, and what it costs, before any work starts.

Get a Free Quote Call Nas — 0455 455 644