Mazda Problems

Mazda’s 6 has always had a pretty good reputation in the trade for its reliability and durability, but globally, there have been a few concerns with the automatic transmission. The first of those is a situation where the transmission goes into limp-home mode. At that point, it can suffer slurred shifts and a lack of acceleration. It doesn’t seem a common complaint in Australia, but it’s reckoned to be caused by the transmission fluid becoming contaminated with small iron particles (possibly swarf from the production process) becoming attracted to the magnetic sensors inside the transmission. At that point, the sensors lose the plot and the information going to the computer becomes garbled.

The other thing seen (mostly in the US) has been a whining noise from the transmission. Inspections have shown this to be caused by a damaged bearing in the transmission, possibly the victim of misalignment of the gearbox casing. Again, it’s not a common fault showing up here.

Overall, the Mazda 6 seems one of the better bets out there in reliability terms.

Mazda Australia has previously told CarsGuide that it would love to get hold of a batch of the hot-shot Mazda 3 Turbos. And while the local arm of Mazda has asked head office for a batch of the all-wheel-drive hot-hatches, no decision has been confirmed as yet.

Mazda’s problem is justifying the cost of making the car in right-hand-drive form, and the complex mechanical packaging makes that even more difficult than usual. Designed for the North American market, the lack of a right-hand-drive variant will likely be the biggest hurdle to the car making it into showrooms here.

Mazda Australia is obviously keen on the idea as it would give it a competitive product to tackle the success of the VW Golf GTi, the Renault Megane RS and the soon-to-arrive new Subaru WRX. The bottom line? Cross your fingers, but don’t hold your breath.

Your car is certainly exhibiting the signs of a car with a blown head gasket. The smoke from the exhaust is one symptom, and so is the loss of performance. The oil leaks, could be part of the same problem, but could also be from somewhere else on the engine. Oil leaks have a cunning habit of being able to hide their true source.

On top of that, even the exhaust smoke and lack of performance could be down to something other than a head gasket problem, so the next step is to take the car to a workshop and have what’s known as a TK test carried. This test will chemically detect if combustion from the engine cylinders is finding its way into the coolant. If it is, you can be pretty sure that you have a blown head gasket.

At that point, you need to weigh up the cost of repairs to see whether you think it’s worth doing, given the overall condition of the car versus the cost of getting into something newer. If you really love the Mazda as much as you say, then maybe the cost of changing the head gasket will be acceptable compared with how you value the vehicle. And even if the repairs cost $2000 or even $3000 (which they could depending on how deep into the engine you need to go and what else you find wrong) there’s not much out there in today’s market for that money that represents anything even remotely decent.

Probably the most common cause of difficult hot-starting in a diesel engine is wear in the fuel pump. If the pump can’t generate the correct pressure due to wear, which is exacerbated by heat, then it may not generate the pressures required to operate the fuel injectors.

This particular engine has a fuel pump which has been known to wear and allow the fuel inside it to overheat, causing the vehicle to go into limp-home mode. But the engine (and many others like it from other brands which use common-rail injection technology) are also notorious for wearing out their fuel injectors over relatively low kilometres. Worn injectors could also be a cause of difficult hot starting.

The Mazda 3 timing belt or chain question is a common one, but one with a fairly simple answer. Unless the Mazda 3 in question is the very first turbo-diesel model (sold in Australia between 2007 and 2009) then the engine powering it uses a timing chain rather than a rubber belt.

The exception was the 2.0-lire turbo-diesel which used a rubber, toothed timing belt. The design seems sound, however, and Mazda’s recommended replacement interval for the belt and its tensioner is every 120,000km. Make sure this has been carried out promptly, as a snapped belt will probably destroy the engine. A small sticker somewhere in the engine bay should record the most recent belt change. The complete kit to replace the timing belt on this engine is available for around $200 and you should budget another few hundred dollars to have the job carried out by a workshop. Best practice is to also change the water pump and thermostat at the same time as these live in the same area of the engine.

The task of the timing chain or timing belt is exactly the same: They take drive from the engine’s crankshaft to the camshaft and, in the process, keep all the moving parts in harmony. Many car makers moved away from a timing chain to the rubber, toothed drive belt as a way of simplifying engine design and driving down the cost of each engine. The rubber timing belt is also quieter in its operation and is also less prone to stretching (as a timing chain can) so the camshaft (commonly referred to as the cam) stays in perfect synch with the rest of the engine’s rotating parts. The rubber belt is a simpler design because it doesn’t need to be tensioned via oil pressure from the engine as many timing chain systems are.

The timing chain, meanwhile, is preferred by some manufacturers because it should last the lifetime of the engine and never need replacement. This isn’t always the case, however, and some engines designs from a variety of manufacturers suffer problems in this regard. But, in a properly maintained engine of sound design, the timing chain should never need attention, while the rubber timing belt generally has a replacement interval of between 60,000km and 120,000km, depending on make and model.

It sounds awfully like the car has entered what’s called limp-home mode. As the name suggests, this allows the ute to run just enough to get you to a workshop without damaging anything else. Limp-home is usually associated with a problem in one of the car’s systems, whether that’s electronic, fuel-system, exhaust system (DPF) or a mechanical fault with the engine or transmission. It’s kind of a self-preservation function.

The good news is that you’re still well and truly overed by the factory warranty, so it’s back to the dealership for your BT-50. This is absolutely Mazda’s problem, not yours.

There are lots of really good choices in tyres for popular models such as the Mazda 3. You can shop online and find cheap tyres, but a much better idea is to actually contact (or visit) a tyre shop who will be able to guide you according to what you want from the tyres.

Some tyres have better life, some offer more grip, some are aimed at fuel efficiency, others are designed to run quietly and some are sold entirely on price. Some tyres will combine some of these traits, while others will be quite focussed on their priorities (performance tyres, for instance, often trade off lifespan and quiet operation for ultimate grip).

So talking to a person who sells and fits tyres every day, is a good place to start. Listen to the advice and proceed from there. There’s no need to ignore some of the Chinese brands these days, either; some of them are quite good and offer a good balance of performance and price. Most tyres are made in China today anyway, even if they’re a familiar brand. Speaking of price, expect to pay around $100 to $150 for a good quality tyre and don’t forget to have them balanced and the car’s wheel alignment checked at the same time. A good tyre shop can do all of this in the time it takes you to do your shopping and can offer advice that an online retailer simply can’t.

And don’t forget that car tyres remain a great example of the notion that you’ll only get what you pay for.

What you might find is that the loss of power and the squealing noise could be completely unrelated. In any case, a loss of power can be caused by any number of problems, so an electronic scan of the car would be the first move in diagnosing that problem.

You might be on the right track, meanwhile, in thinking that the squealing noise has something to do with the rubber drive-belts in the engine bay. These will often emit a high-pitched squeal if they get moisture on them. Typically, this will be coolant from a leaking water pump or a leaking radiator (both of which are located handily near the belts). Even though the belts may be perfectly tensioned, coolant leaking on to them is definitely capable of producing the noise you’re hearing.

Unless you’ve changed the way you drive, a sudden jump in fuel economy suggests something wrong with either the mechanical or electronic side of things. Have the vehicle scanned and see if it throws any fault codes. From there, you can work out what component is giving you grief and target the problem accurately, rather than mess around for weeks flying blind.

One reason for the sharp increase in fuel consumption could be that the vehicle’s diesel particulate filter (DPF) is full and needs to be regenerated. If you’re not doing long, highway miles, the computer can take matters into its own hands and dump extra fuel into the exhaust system in an attempt to get the exhaust hot enough to regenerate the filter. But you could also be dealing with a faulty fuel-pressure regulator, worn injectors or even something as simple as a blocked air filter.

The popular MG3 is the model you’re referring to and you’re right; it hasn’t been locally crash-tested. But it does lack some important safety gear. Enough, we reckon, to knock it off your short-list. The MG lacks, for instance, important driver aids such as autonomous emergency braking, blind-spot monitoring and lane-keeping assistance, nor can these features be had by spending more on a fancier version.

Which leaves us with your other two choices, the Hyundai i30 and Kia Rio. Even then, you’ll need to option up beyond the base-model to get (some of) those safety features, but these are not expensive cars to begin with, so the jump might not be as bad as you think.

The other car to consider would be the SP Pure version of the Mazda 2. At $23,690, it’s not over-priced but it does have low-speed (up to 30km/h) autonomous emergency braking, blind-spot monitoring and lane-departure warning as well as rear cross-traffic alert.

And a manual transmission? The MG 3 no longer offers one, both the Hyundai i30 and the Kia Rio are available with a six-speed manual option. The Mazda 2 Pure SP is automatic only, but you can get a six-speed manual on the base-model Mazda 2.

I agree that youngsters taught to drive a manual car tend to be better drivers, but that’s not a universally held view these days. And the fact is that most young drivers will never be presented with a clutch pedal in the future, raising the question of why learn in the first place? The reality is that learning to drive a manual car gives you extra mechanical awareness and extra ability to multi-task behind the wheel.