Holden Colorado Problems

The trick to a diagnosis here might be to find out what rotational bits and pieces are involved. To do that, you need to work out whether the noise is wheel-speed related, driveshaft-related or engine and transmission-related. The driveshaft spins fastest, followed by the driveshafts and finally the wheels, axles and brakes. So that’s probably the key to it.

Even something as simple as a bent or loose brake shield can cause a rattle, squeak or grinding noise, and some owners have gone so far as to strap GoPro cameras under the car and take it for a drive to see what’s going on. A mechanical workshop will probably be a bit more scientific, but the basics of troubleshooting remain the same.

As far as the driveline locking for a moment, you could be looking at a related problem or a completely separate issue. It’s probably wise to make sure the transfer case isn’t suddenly shifting into neutral or low-range on its own for that split-second, as that could cause driveline chaos. But a sticking brake caliper or faulty ABS module could potentially also cause the same sensation.

Some cars cycle their ABS systems when you first start up and take off, and this can lead to a metallic noise for a second or two and a slight buzz through the car. It can be intermittent, too. Are you sure that’s not what you’re hearing?

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.

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.

Manual gearboxes generally work better/more smoothly when they have some heat in them and the oil gets a little thinner and better able to lubricate. So you’re right on that account. If the gearbox was crunching on every gearchange, you’d also probably suspect the clutch might be worn, too. But since it’s only the one gearchange that’s making the noise, then your theory that the synchromesh rings are worn holds water.

But before you do anything drastic, make absolutely sure the clutch is disengaging fully and that all the clutch lines and pedal action are spot on. A dodgy clutch can also produce this sort of crunching noise. And, yes, it can be worse when the vehicle is cold.

Meanwhile, for some reason, the synchromesh on second gear is the one most likely to fail on the majority of cars (probably because second gear cops and awful hiding and copes with very high loads). So, in that sense, yours is a copy-book case of worn synchros. (First gear is also highly loaded, but since you only really shift up from first – hardly ever down to first on the move – its synchromesh rings don’t cop such a spanking.)

If the problem gets worse, you’ll probably find the upshift from first to second will also start to graunch. That’s when you’ll know for sure that the synchros need replacing. As you point out, though, to really diagnose this the fault requires an inspection of the parts and that means the gearbox out and pulled apart. While you’re in there, change the other synchromesh rings and the transmission’s bearings. And don’t put it back together without a new clutch.

In the meantime, however, if you’re prepared to shift very slowly and carefully while the vehicle is cold, you can actually drive around this problem. Many car owners have done so for years without further problems. Not best engineering practice, perhaps, but it’s a money saver.

You may have a collection of problems rather than just a single one. The vibration through the steering wheel could simply be the vibrations from the diesel engine travelling up the steering column and into your hands. Does the vibration go away when you rev the engine to just off idle? If so, perhaps an adjustment to the idle speed is all that is required there to move the engine out of its resonant patch.

A vibration in the cabin could be a worn wheel bearing, out-of-balance driveline, a worn torque converter, broken or worn engine mount, broken exhaust mount, damaged tyre, a wheel out of balance and plenty more. But the play in the front driveshaft coupling would be a smart place to start looking. Again, the problem comes and goes because of the harmonic periods inherent in things that spin very quickly. Any out of balance problems can easily show up as transient vibrations inside the car.

Noises like this are mostly temporary and are caused by a small rock or some other foreign object becoming jammed between the brake disc and the brake pad. Often, a sharp jab of the brake pedal (when it’s safe to do so) will dislodge the object and peace will be restored.

But if you’ve replaced the wheel bearings, then you’ve already had to remove the brakes. So unless the stone or whatever is lodged deep in the brake pad material, that’s probably not the cause here. Which means you need to look more closely.

The ABS sensor is an interesting theory, but I’d imagine if the clip had broken and dived into the front end anywhere, you’d have an ABS warning light on the dashboard by now. Perhaps it’s something to do with the front hub or the front driveshaft assembly. Perhaps a CV joint? Check for damage to the CV joints’ rubber boots. Don’t rule out a pothole having wrecked your wheel alignment, at which point what you’re hearing is a front tyre being torn to shred.

And what about the power steering system. These can squeal when they’re low on fluid, have air in the system, the belt is slipping or the pump itself is worn out.

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.

If yours is a vehicle with the rotary knob that selects four-wheel-drive (rather than the old fashioned gear-stick method) then you might have a faulty or poorly adjusted switch. While these electronic switching systems were deemed to be an improvement for the driver, many find that the switches sometimes refuse to effect the desired gear or drive-mode selection which, if you suddenly find yourself needing to engage four-wheel-drive in a hurry, can be frustrating to say the least.

You may find some contact-cleaning spray might clean the switch up, but you may also need to remove the rotary switch to either clean it or replace it.

If the problem is not with the switch itself, you may have some other kind of electrical glitch or maybe even a mechanical engagement problem with the transfer-case.

Many cars will give a beep if they think the car has been locked with a door, bonnet, boot or window open, even slightly. But if you’re checked all that and everything is secure, the first thing to try is to reset the car’s body computer. The first way to try is to hold the lock button down on the remote for about 30 seconds. Sometimes this will force a reset.

If that doesn’t work, disconnect the car’s battery overnight and reconnect it next morning. You will have to rest your clock and radio station presets, but this will sometimes restore the computer to its factory settings. If none of that works, you may have a dud micro switch that’s giving the computer bad information, or the body computer itself may be on the way out.

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.