Holden Colorado Problems

As a modern, conventional design, your Holden is negatively earthed (or, grounded). That is, the negative terminal of the battery is connected to the car’s body and engine to complete the circuit for the electrics to function.

But it wasn’t always this way, and in the USA and particularly Britain, many makes and models were positively earthed. Farm machinery and motorcycles were also often positively earthed. I’ve even heard that Dodge cars from the 1920s and 1930 were positively earthed in Canada, and negatively earthed in the US.

There’s a theory that negative earthing is better for preventing corrosion due to electrolysis, but it seems not all engineers agree on this. Ultimately, negative earth is the conventional setup today. Just make sure you don’t get it wrong as hooking up a battery the wrong way around in a modern car is a fair chance to blow the computers and other electronics to smithereens.

That the shudder only occurs in fifth gear is, perhaps, the big clue here. If the problem was an engine mount or drive-shaft or suspension problem, the shudder would appear at those same engine revs or road speed, regardless of what gear the car had selected. So maybe you need to dig a bit deeper into the transmission to see if there’s a problem with the torque converter, the way the converter lock-up is working or even a problem with the gearset itself that offers up fifth gear. This is, of course, if the vehicle is an automatic (which you haven’t disclosed).

If it’s a manual, then fifth gear is the overdrive ratio for that gearbox and some Colorados were fitted with five-speed manuals that had a problem with the thrust washer on fifth gear. This washer could fracture if the vehicle was used for towing heavy loads. When the washer finally failed, the vehicle could jump out of fifth gear and actually lock up the rear wheels. Back in the day, Holden was actually replacing the entire gearbox if the vehicle was one of the affected ones. It would be worth checking with a Holden service centre to see if your vehicle is from that batch.

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.

Not every Colorado suffers this problem, but there are certainly a percentage that do. It’s a relatively common thing with this model and the first sign is a stain that develops on the roof lining in the rear seat just above the rear window. It’s caused by water entering the cabin through the high-mount brake light assembly.

The problem is caused by the light’s seals that fail over time, and the fix is to remove the light, clean the area around it and then seal it with panel sealer (or something similar) from the outside. If you’re fussy, you can replace the whole light assembly, but that won’t fix the failed seal, so you’ll still need to reseal the area where the light mounts.

You really can’t afford to take any chances with a car’s steering system. The thought of this crucial system failing even at low speeds doesn’t bear thinking about, so if there’s any play or looseness in the system, it needs to be diagnosed and fixed properly with new parts if necessary.

Meantime, Loctite and other thread-locking products are designed to stop fasteners coming loose. These products are not designed to take up slack in worn parts and shouldn’t be used that way. Even if the thread-locker stops the fastening nut coming loose, it won’t do anything about the slack in the joint you’ve already noted.

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).

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.

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

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.

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.