Holden Colorado Problems

It’s quite common for an oil pressure sensor to develop a fault where it sends the incorrect information to the car’s computer which then lights up the low oil pressure warning. But since you’ve already replaced this sensor, maybe that’s not the case here.

The big clue is that fresh oil and filters improved things a little, which makes me think it’s a genuine oil pressure problem. I also reckon you might be bang on the target by suggesting that it’s an oil pick-up problem. The oil pick-up lives in the sump of these engines and if the pick up inlet is blocked or partially blocked by sludge from the engine, it can fail to suck up enough oil to maintain the correct oil pressure. The higher the revs, the bigger the pressure shortfall. Failing that, sludge can block the various oilways around the engine that allow the oil to get to where it needs to be. Either way, you wind up with insufficient oil pressure and flow and risk destroying the engine.

I wouldn’t have thought 136,000km on an engine would have it showing signs of oil sludging, but that’s based on proper maintenance (not to mention that even modern diesels are filthy things inside). Have you owned the vehicle from new? Has it always been serviced correctly and promptly? If it’s been neglected (even one skipped oil change) it can develop the deadly sludge and it can be all downhill from there.

Possibly the best course of action would be to remove the sump and check the oil pick-up strainer for signs of gunk and build up. If that’s okay, then two or three quick oil changes (say, every 1000km) with an engine oil designed for trucks (which has lots of detergent as an additive) might clean things up internally enough to keep the oil pressure light at bay.

The other thing to try would be a new oil pump. Like any engine component, these can wear out over time and kilometres but, again, I wouldn’t expect to see significant wear on one that’s just 136,000km old. Other causes to consider would be excessive bearing clearance in the engine (due to wear or damage). In that case, a tear down and rebuild is the best option, because worn engine parts don’t repair themselves.

Commercial vehicles like the Colorado can often lead a much harder life than passenger vehicles. And that means some areas can wear faster, differential bearings being just one of them. A Colorado that has been used to carry heavy loads or tow heavy trailers could easily be showing wear in the differential at this point.

The other thing that destroys differentials is driving the vehicle through water crossings. As an off-road capable vehicle, this is pretty likely in a Colorado., What happens is that water can enter the differential housing through the breather tube and contaminate the diff’s oil. At which point, wear is accelerated as the differential gears and bearings are no longer receiving the lubrication they need. Floodwater is particularly bad for diffs as it also contains lots of tiny grit particles which act as grinding paste inside the differential.

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.

No, there was only one automatic gearbox, a six-speed unit that was vastly more popular than the other choice, a six-speed manual. For the 2017 model year, Holden upgraded the automatic transmission with what’s called a centrifugal pendulum absorber torque converter.

This absorber was a type of dampener designed to reduce vibrations form within the torque converter and improve the driveline’s smoothness. But this was applied to all 2017 Colorado diesels, meaning the transmission differs from a 2016 or earlier unit.

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).