Holden Commodore: Carbon build-up on the intake valves of the SIDI direct-injection V6 (3.0 and 3.6)
Carbon build-up on the intake valves of the SIDI direct-injection V6 (3.0 and 3.6) is a common engine fault on the Holden Commodore on the 2009–2017 cars, and we rate it major. Putting it right costs $700 to $1,600 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 51 documented faults on the Holden Commodore.
- Vehicle
- Holden Commodore
- Engine
- 3.0L / 3.6L / 2.4L / 2.5L / 2.8L / 3.2L / 3.5L / 3.8L / 4.3L
- Years
- 2009–2017
- Fuel
- petrol
- System
- Engine
What you are looking at
No photograph available
What goes wrong
From late 2009 Holden moved the 3.0 and 3.6 litre V6 to spark ignition direct injection, which sprays the fuel straight into the cylinder instead of over the back of the intake valve. Nothing washes the valve stems any more, so oil vapour from the crankcase breather and blow-by bake onto them as hard black carbon. The car gets slower to start, misfires, throws misfire codes and quietly loses fuel economy, and the misfire cannot be cured by new plugs, coils or injectors - workshops chase these for months before the intake comes off and the real cause is found. The fix is to have the valves blasted clean with crushed walnut shell, and it has to be repeated as the kilometres build.
What you would notice
- Long crank before it fires, worst on a cold morning
- Rough idle and a misfire that new plugs and coils do not fix
- Check engine light with misfire codes
- Fuel economy noticeably worse than it used to be
- Hesitation or stumble under light throttle
How to check it
Where to look. Inside the intake ports on both cylinder heads, under the intake manifold in the vee of the engine.
Ask the seller to leave the car untouched overnight so you can hear the first cold start of the day, and count how long it cranks before it fires, because a healthy one catches almost straight away.
Sit in the driver's seat with the engine idling and rest your hand on the gear lever and the centre console to feel for an uneven shake or a repeating stumble.
Watch the dashboard on start-up and again at the end of the test drive to see whether the check engine light comes on or stays on.
On the drive, hold a steady light throttle around 1,500 to 2,000 rpm and feel for a stumble or hesitation.
Ask whether the intake valves have ever been walnut blasted or cleaned and ask to see the invoice, because it is a job that gets repeated.
Ask what the car actually returns for fuel and compare that with the figure in the sales listing.
If a workshop inspection is possible: have the stored misfire history read from the engine computer and have a specialist borescope the intake ports to grade how bad the carbon is.
What it costs to put right
$700 to $1,600 at New Zealand independent workshop rates. That is for this job on its own, not for the car.
Ask the seller
- “Have the intake valves ever been walnut blasted or cleaned?”
- “Has it ever had a misfire, and what was done about it?”
- “Has an oil catch can been fitted?”
- “How long does it crank before it starts on a cold morning?”
Now check the Holden Commodore you are actually looking at
Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.
Where this comes from
- AustralianCar.Reviews 'Recalls & faults: Holden VE Commodore (2006-13)' - carbon deposits on SIDI intake valves causing hard starting and misfires
- RevHigh workshop write-up 'Fixing the Unfixable: Holden LFX SV6 Misfire Solved with Walnut Blasting'
- JustCommodores forum thread 'SIDI Intake Valve Cleaning?'
- Whirlpool Forums thread 'VE SV6/Calais known issues'
Holden Commodore buyer questions
Is carbon build-up on the intake valves of the sidi direct-injection v6 (3.0 and 3.6) serious on a Holden Commodore?
We rate it major and common on the Holden Commodore. From late 2009 Holden moved the 3.0 and 3.6 litre V6 to spark ignition direct injection, which sprays the fuel straight into the cylinder instead of over the back of the intake valve. Nothing washes the valve stems any more, so oil vapour from the crankcase breather and blow-by bake onto them as hard black carbon. The car gets slower to start, misfires, throws misfire codes and quietly loses fuel economy, and the misfire cannot be cured by new plugs, coils or injectors - workshops chase these for months before the intake comes off and the real cause is found. The fix is to have the valves blasted clean with crushed walnut shell, and it has to be repeated as the kilometres build.
How much does it cost to fix on a Holden Commodore?
$700 to $1,600 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.
Which Holden Commodore years are affected?
Our research records this fault on the 2009–2017 Holden Commodore. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.
How do I check for it before I buy?
Ask the seller to leave the car untouched overnight so you can hear the first cold start of the day, and count how long it cranks before it fires, because a healthy one catches almost straight away. Sit in the driver's seat with the engine idling and rest your hand on the gear lever and the centre console to feel for an uneven shake or a repeating stumble. Watch the dashboard on start-up and again at the end of the test drive to see whether the check engine light comes on or stays on. On the drive, hold a steady light throttle around 1,500 to 2,000 rpm and feel for a stumble or hesitation. Ask whether the intake valves have ever been walnut blasted or cleaned and ask to see the invoice, because it is a job that gets repeated. Ask what the car actually returns for fuel and compare that with the figure in the sales listing. If a workshop inspection is possible: have the stored misfire history read from the engine computer and have a specialist borescope the intake ports to grade how bad the carbon is. Look here: Inside the intake ports on both cylinder heads, under the intake manifold in the vee of the engine.