Holden Colorado Engine Problems

Any vehicle of this age can start to experience wear in the turbocharger. These units live a very hard life, spinning around at something like 250,000pm and operating in a very hot environment. Cracks can occur in the housings, the bearings can wear and even the blades of the turbocharger itself can break or become bent. All of these things will affect performance. And, unfortunately, it sometimes doesn’t matter how well the vehicle has been maintained. Turbos have a finite lifespan and that’s all there is to it.

But don’t simply assume that a lack of performance is due to turbocharger failure or wear. Sometimes on this model, the Exhaust Gas Recirculation (EGR) valve, which is designed to re-burn some of the engine’s exhaust to reduce tailpipe emissions, can become stuck open, reducing boost pressure and, therefore, performance.

Many workshops specialise in turbo-diesels these days, and should be able to help with a diagnosis.

Just because you can’t see where coolant is escaping, doesn’t mean it isn’t. Equally, a lack of milky oil in the sump does not guarantee that the problem is not a head gasket-related one. Even an external leak from a hose or fitting can be hard to track down as the hot coolant evaporates before you have time to find the witness mark or the coolant drips on the garage floor.

Your best bet is to have the car’s cooling system pressure tested. A mechanic will pressurise the system and leave it for a period of time. If the system holds pressure, that’s a good sign that there’s no leaking. If it loses pressure, you have a problem somewhere in the closed-loop cooling system. That could indicate a problem with a radiator, hose, water pump, head gasket or even a split bore or cracked cylinder head.

But there’s one other check to make that might save you a lot of time and hassle. Takle a close look at the car’s overflow tank. This is also called the expansion tank and is designed to catch coolant as it expands (through engine heat) before allowing that extra coolant to return to the engine as the car cools down at the end of the trip. If this tank is leaking (even from a tiny crack) coolant that expands into it will be lost and the cooling system will appear to be continually losing coolant.

The starter motor would be a very good place to start looking for the problem. If the battery checks out (and that presumes you’ve load tested it, not just run a voltmeter across its terminals) and the addition of a second jump battery only just turned the engine over, then, the starter motor is a likely suspect.

But don’t forget things like a poor earth somewhere on the car or a dodgy ignition or starter button. Once the engine is running, check the power going into the battery. You should be looking at between 13.2 and 14.5 volts going into the battery with the engine running if the alternator is pulling its weight.

Just because the battery indicator is showing green, does not mean categorically that it’s in good health. It can produce a surface charge that might show 12 volts with no load on it, but can fall to its knees when you load it up with the starter motor.

The biggest issue owners have experienced with this car is a tendency for the engine to consume oil and require a top-up between oil changes. Holden addressed this by changing the specification of the oil from a 5W30 to a 5W40 oil and released a new oil cap design. You’ll know if the new-design oil cap is fitted to your car as the owner’s manual will have been altered by a Holden dealer to reflect the new oil specification.

Beyond that, the biggest driveline complaint seems to be the noise generated by the engine. However, this seems to be a natural by-product of the 2.8-llitre turbo-diesel fitted to the Colorado 7 and is not a fault per se.

It sounds counter-intuitive that an engine would run at all with the crank angle sensor removed. Generally, without this sensor working properly, the fuel-injection system has no idea when to inject the fuel or fire the spark plugs. But sometimes – as in this engine – if the computer can't 'find' a crank angle input, it will take a reference from the camshaft angle sensor and use that to time the injection and ignition.

Even so, if the problem persists after two replacement sensors, it's probably fair to say this particular sensor is either not the root of your problem, or that or the engine's wiring is frying the new sensors as fast as you're changing them.

Either way, a trip to an auto electrician seems like the next logical step. Chances are a switched on sparkie will have seen this exact problem before and will know how to deal with it or at least take the logical steps to diagnose what's going wrong. Simply continuing to change bits and pieces is often an expensive way to solve a problem like this.

A diesel that will turn over but not fire will often have a problem with its fuel system as the cause. You may need to check the fuel pressure and the pump itself, but other causes can be blocked or worn injectors and blocked or dirty fuel filters. A car with faulty glow-plugs can also be difficult to start from cold. But even things like a blocked air filter or something else fundamental to the car's operation could be the cause. And while it sounds simple, is there actually fuel in the tank?

If the solution doesn't present itself simply, the best advice is to have the car electronically scanned to check for fault codes the on-board computer will have logged.

Any excess smoke from a diesel engine can mean a too-rich mixture. So are you certain the injectors are the correct ones for that engine? Has a sensor been bumped during the replacement process that is not sending the right signal to the computer that controls the injection on a modern turbo-diesel?

Also, cold-start problems in an engine like this are often traced to the glow-plugs. These are crucial to warming up the cold engine internals so that combustion will take place. So perhaps a check of the glow-plug wiring is in order as this could have been disturbed while the injectors were being replaced.

Has anything else been changed or replaced as part of this process? Has the engine been sitting for an extended time (allowing the fuel to go stale)?

There could be a complex, electronic, fuel-supply or engine-management reason for this, and if that's the case, having the vehicle scanned would be a good place to start. Or, it could be a case of human behaviour that is skewing your fuel economy figures.

By which, I mean that when you got the car brand-new, you gave it the kid-gloves treatment, understanding that the brand-new engine needed to be run in and would appreciate a slightly easier start to life. Then, as the novelty wore off and the vehicle began to earn its living, you subconsciously grew a heavier right foot. And it is this that's seen the fuel consumption creep up.

Failing that, you might have an on-board computer that has been silently recalibrating itself, perhaps in conjunction with software updates at the dealership which you may, or may not have, been made aware by the dealer. To be perfectly honest, I'd find 6.4-litre per 100km average on a Colorado borderline unbelievable, and the sort of economy only a dedicated fuel-saving driver could even get close to. Ten litres per 100km, meanw

I think you’re on the right track by concentrating on the information being conveyed by the crank-angle sensor. But the problem is more likely to be a stretched timing chain rather than a dud sensor. The V6 engine in your Colorado is notorious for this problem and, when it happens, it throws the camshafts out of synch with the crankshaft. When the crank-angle sensor and the camshaft-angle sensor can’t agree that the positions of the crankshaft and camshafts relative to each other are correct, the problems start.

This lack of synchronisation is one of the things the crank-angle sensor is paid to look for and why it’s limiting engine speed or not allowing the engine to start at all. By clearing the fault code and disconnecting the crank-angle sensor, you’re stopping the error information being sent to the ECU and the ute starts first time (it’s probably taking a camshaft-angle reference when it can’t find the crank-angle information).

Modern vehicles like the Colorado have lots of sensors to help prevent major engine melt-downs. One of those is the sensor that tells the car the engine oil level is too low for safe operation. If that sensor is sending bad information to the car's computer, the vehicle might be programmed to go into limp-home mode or even shut down altogether to preserve the engine.

But the oil problem the car is reporting could also be dangerously low oil pressure or oil that has become too hot. The farther and faster you travel, the hotter the oil becomes (up to a point) and the thinner it becomes, meaning it may not be thick enough to sustain safe oil pressure. This could also be caused by a dud sensor, but it could also be a real situation. And like the low oil level sensor, this can force the engine into shutting itself down as a self-preservation measure.