Holden Commodore Engine Problems

First thoughts would be that you have a fuel injector that is not spraying either the correct amount of fuel and/or in the correct pattern for proper combustion. This will certainly bring on the symptoms you’re seeing, as well as ruining fuel economy. It’s also most likely to show up if the engine has been sitting for a while.

But the reality is that a modern engine like this one has literally hundreds of electronic sensors and systems that can all add up to poor running and economy. The best bet is to have the car scanned to see if the on-board computer has logged any faults. Without this intelligence, you’re flying blind, replacing parts that may or may not fix the problem.

There are literally hundreds of things that can cause a check-engine light in a modern, computer-controlled car. A problem with the ignition, fuel system, emissions-control system, air-intake, lubrication, cooling and much, much more can cause this light to illuminate.

The best way to proceed is to have the vehicle electronically scanned. That way, the computer can tell the mechanic where the problem is and, hopefully, precisely what’s causing the check-engine light to flicker on.

For the record, however, a common fault with the V6 engine in this series of Commodores is a stretched timing chain that the computer interprets as incorrect valve timing (which it is). Plenty of owners of this model have discovered this as the cause of their check-engine light.

The first thing to do is make sure your battery is earthed properly and all the relevant electrical contacts are tight and clean. Low voltage or a poor connection can easily cause the problems you're seeing, especially if they've all occurred more or less at the same time.

The next thing is to have the vehicle electronically scanned. That will tell you what faults the on-board computer has spotted, and you can then tackle them logically instead of replacing parts that don't fix the actual problem. The rough running could be anything from a dud oxygen sensor to a fuel-injection problem and lots in between.

I would suspect the heating and air-conditioning problems are separate to the engine's poor running, but anything's possible when a car's electronics start playing up.

It's good news. Your car is indeed compatible with E10 fuel which means you can use the slightly cheaper fuel without risking damage to your vehicle. The car should also run exactly the same as it does on normal unleaded petrol, although you may find you use slightly more fuel per 100km. This should, however, be more than offset by the savings you'll make at the pump.

Both those models of Holden used the same engine; the L36 (Holden's internal code) Ecotec V6. As such, you should be able to fit the engine from the VT Commodore into the Statesman with very few other changes. The biggest hurdle will be if the Commodore donor car was a manual-transmission vehicle, as the ECU may be different to the Statesman's unit to allow for control of the electronic transmission. The best bet is to retain the Statesman's wiring and computer and change over only the engine hardware from the Commodore.

The other (minor) catch is that the VT's version of the V6 was tuned for 147kW, while the later version of the same engine in the Statesman was good for 152kW. There was a small torque difference, too (304Nm plays 305Nm). So you'll be trading off a small amount of performance but, realistically, not enough to notice.

Based on the symptoms, it sounds like something is getting hot and shutting down. When you leave it to cool for those 10 minutes, it fires up again. This could be something in the ignition system becoming too hot, or the fuel system (fuel pump) or perhaps even fuel vaporisation.

However, the V6 engine in your Commodore is very well known – notorious, even – for a crank-angle sensor that can stop working when it becomes too hot. This is a condition that seems to set in with age and, as the sensor becomes less tolerant of heat, will simply shut own the engine with no warning. Here’s something to try next time it happens: Identify the sensor in question (it’s located down by the front pulley of the engine’s crankshaft. Keep a bottle of tap-water in the car boot. When the engine stops next time, open the bonnet and pour the cool water on to the sensor. In many cases, the water is enough to cool the sensor and the engine starts right up. Definitely worth a shot before you start replacing other bits and pieces.

Assuming your car is a V6, I’d recommend a quality brand of oil with a viscosity of either 5W30 or 10W40. Provided you buy a quality, known brand, it will have all the additives that make modern multi-grade oils so much better than the oils that went before them. If your car runs on LPG (as many Commodores do) then you need to buy an oil that’s designed for use with this fuel. Fundamentally, though, the same rules apply: Stick to the correct grade and weight of oil and only use a quality brand, not the generic-branded supermarket stuff.

The actual oil capacity for a V6 Commodore of that vintage is 5.3 litres, so if you buy a six-litre pack, you’ll have enough for tops-ups between oil changes. Don’t forget to change the oil filter, too. While some mechanics reckon changing the filter every second oil change is enough, the wisdom of putting nice, clean oil through a dirty filter is beyond me, especially considering an oil filter costs only a few dollars.

Changing your engine’s oil is probably the best engine insurance you can buy. But you need to do it properly, so a workshop manual is probably a good thing to have as well as it should walk your through the process (important the first time). You also need to be able to dispose of the old oil and filter in an environmentally responsible way, too. But this is a great first maintenance job for the budding home mechanic and can really save you some money over the years. Good luck with it.

There are many, many things that can make a car overheat. A faulty radiator, collapsed radiator hose, jammed thermostat, blown head gasket, low coolant level, incorrect ignition or camshaft timing, faulty fuel injectors, the list goes on and on. So you need to have the car scanned electronically to see if a fault code is offered up that could be the cause or part of the problem. First, though, I’d have a close look at the obvious stuff like a leaking radiator or blown radiator hose to make sure that it’s not a really simple fix. Even a faulty radiator cap – as simple as that sounds – can lead a car to overheat.

To be honest, a 34-dgree ambient day should never be enough to make a modern car overheat, especially not one like a Holden Commodore which was designed here to easily cope with our weather and temperature extremes.

It’s interesting to note that you bought the car from a dealer, so it would be worth going back and checking the paperwork to see if the car was sold with any warranty. It’s doubtful, however, as a 2005 model car falls outside the boundaries of Victoria’s statutory warranty legislation (generally a used car must be less than 10 years old and have travelled less than 160,000km before a statutory warranty applies from a licensed car dealer). A good mechanic who knows this type of car should be able to sort it, but have it checked soon; continuing to drive it with an overheating problem is a sure way to make small problems bigger ones.

The early VE model Commodore V6s certainly had all sorts of dramas with stretched timing chains that could run into thousands of dollars to fix. Holden changed the design of the chain and while it did help, we’ve still heard of later post-2008 model Commodore V6s exhibiting the same problem.

The problem is made worse (accelerated) by poor servicing, so if the vehicle in question doesn’t have an absolutely up-to-date service handbook with evidence of every scheduled service being carried out in full, we’d be walking away. Same goes for a car that rattles on first start-up, won’t idle properly or has a check-engine light illuminated on the dashboard.

A problem like this could be caused by any number of things, James. Electronically interrogating the on-board computer is a wise first step, as the error codes that will result will possibly lead you straight to the offending component.

In cars like yours with electronic fuel-injection and engine management, there’s an array of sensors that need to send the correct signal to the car’s on-bord brain for everything to function properly. Replacing these sensors one by one until you fix the problem is a very time and cash consuming way of proceeding. Have the car scanned instead and see what fault codes show up.

Meantime, if I had to venture a guess, I’s say the problem sounds ignition related. An engine will often idle properly with no load on it, but when you select a gear, there’s suddenly load applied and, if the ignition system is not spot on, the engine can suddenly do all sorts of crazy things, including dropping cylinders. The other thing that occurs to me is that your battery might be low on charge. Injected engines absolutely do not like a lack of volts.