Toyota Problems

The clue here is that the problem started after the repairs were made post-crash. It sounds awfully like some of the turbocharger's plumbing has been damaged/gone missing after the crash. If so – and it only takes a minute crack in the piping – the engine can lose turbo-boost, which will produce the precise symptoms you've noted.

While the turbocharger itself will be working fine, the boost it produces is being allowed to escape into the atmosphere instead of being pumped into the engine to produce more power. That's why it sounds noisy, and also why it's not delivering the performance you're expecting.

There are probably hundreds of reasons for this to occur, starting with the fuel system and including (but not ending with) something to do with the electronics that control modern turbo-diesel engines. Other causes can be clogged EGR valves or faulty injectors. You need to have the vehicle scanned to see if the on-board computer has detected the fault and logged it. But don't rule out something simpler like a fault with the DPF or even a dirty air filter. Either way, black smoke suggests either a problem with the air-fuel mixture or the way it's being burned.

But don't ignore the problem as black smoke from a diesel engine can also mean it's running hot and that can lead to all sorts of problems including internal engine damage. Unlike a petrol engine which will tend to run cooler on a too-rich mixture (too much fuel, not enough air) a diesel running rich can easily run too hot.

It will vary according to what model Prado we're dealing with and, since Australia is now on its third generation of Prado with deliveries starting back in 1996, that's a fair range of vehicles. As a guide, however, a 2009-onwards Prado (the J150 model) has a rear floor measurement of something like 1910mm with the second row of seats folded away.

The best advice we can give you is to grab a tape measure and measure it for yourself. You'll need the tape measure anyway to measure the intended load in the first place.

No that it's any consolation, but Toyotas have, for years, had owners complaining about the Bluetooth connectivity and clarity in some of its cars. In some cases, the dealer has been able to improve things, in others, the owner has resorted to an aftermarket head unit with better Bluetooth performance.

Toyota has been working hard on this and, to be fair, later models seem to be better than ones from a decade or so ago. Again, though, that doesn't help you, nor is it acceptable that a modern car can't nail this now basic connectivity function. The advice would be to keep on the dealer for a fix. You could also call Toyota Australia's customer service division if the dealer can't resolve the issue.

The smart money says go with a Toyota. The RAV4 is popular but within your budget, you'll be buying a 12- or 14-year-old car with at least 200,000km on its odometer. Which still means it's probably a pretty good thing in terms of reliability, provided it's been serviced correctly up to now, but you'd have to buy carefully. A second-hand Kluger can also be a good deal if you can afford the fuel, but comes with the same caveats.

A Honda CR-V won't be much different to the RAV4 in terms of its price versus model year, but you stand a slightly better chance of finding a CR-V with relatively low kilometres. Don't be afraid to get a bit alternative and look at things like the Kia Sportage. Your ten-grand gets you into a Sportage of around the same vintage as the RAV4, but is likely to have as many as 100,000 fewer kilometres on board. Again, check for a full service history.

And given your usage pattern, don't be temped to stump up more for a hybrid SUV; there's just not the pay-off at the pump for a car that does mainly highway and open-road work.

Flushing a transmission is a practice that mechanics around the world just can't agree on in terms of its benefits. Either way, it would be pretty dangerous to do it with something as flammable as petrol. Also, unlike transmission fluid, petrol is not a lubricant so internal damage would possibly occur if you ran the car with only petrol in the transmission.

Most transmission flushing is done by using fresh automatic transmission fluid (ATF) which displaces most of the old ATF. A fluid change is the other service option, but this will usually only replace the ATF in the transmission's pan. A flush, meanwhile, will replace the stuff in the pan as well as in the torque converter and the transmission lines.

Your problem, however, sounds more like a lack of fluid in the first place. The inability of an automatic transmission to select gears and/or produce any forward movement is often down to depleted ATF rather than dirty or old fluid. Check the fluid level on the transmission's dipstick and, if it's low, add some more. The job then is to work out where the ATF is going missing, because the transmission is a sealed system that shouldn't need topping up. You may have a leak somewhere. And definitely check this first before spending lots of money on repairs when a quick ATF top-up will bring the car back to full health.

Air-conditioning can really add another layer of stress to an engine. Since the air-con compressor is driven off the engine (via a belt) it's just another thing for the engine to deal with. And since the engine has to make more power to run the air-con and travel at the same speed, it uses more fuel. And more fuel burned equals more heat, it's pretty basic physics to that point.

Any vehicle with a cooling system that is already a bit marginal can easily be made to overheat by switching on the air-conditioning. So the first thing to do is make sure there are no leaks in the cooling system, the radiator is not clogged internally or covered externally in dead bugs, the radiator hoses are not collapsing when you rev the engine, the water pump is working efficiently and the radiator cap is holding pressure (the boiling point of the coolant rises as you pressurise the system. Again, basic physics: Water boils at 100 degrees-C at sea level, but at the summit of Mount Everest, if you set up your camping stove, you'd boil water at just 68 degrees-C due to the lower atmospheric pressure).

The other thing to check is the condition of the cooling fans. The engine will have its own fan, but cars with air-conditioning usually have a second cooling fan that starts up when the air-con is switched on. You can tell if this second fan starts up by listening for it when you hit the A/C switch. If it isn't coming on (or the engine's fan is broken, slipping or doesn't have the correct shroud fitted) than this can easily lead to overheating.

Plenty of people have successfully converted vehicles like these to motorhomes, so the short answer is yes, it's a good choice. Because it's a bus, however, it will have windows along the full length of each side, so privacy inside might be a problem. Many motorhome builders tend to black out various windows as well as fit security screens over them to make the rig more secure at night and when you're not there to watch over it.

Some early versions of these buses were petrol-engined, but a diesel version would be a much better bet for outback touring where diesel is sometimes easier to obtain. Beyond that, the success of the conversion will come down to how clever you are with things like the equipment you specify and the layout you choose.

Check that the engine-oil dipstick is seated in its tube correctly. If it's not, this could be a great place for oil to escape and become plastered all over the engine. It's the small yellow, plastic loop just below the oil filter. While you're there, check that the oil filter itself hasn't come loose. Try to tighten it by turning it by hand clockwise. If it moves at all with hand pressure, it's loose.

The most likely culprit, however, is the rocker cover gasket. If this seal breaks, oil can be free to migrate out of the engine, right down the side of the cylinder head and crankcase, making the mess you've described. To check, clean the engine with degreaser and water until all the oil is gone. Then take the car for a decent drive, open the bonnet and the source of the leak may be very obvious.

These are quite different vehicles in terms of their physical size. While older generations of the RAV4 were known as compact SUVs, the current model is resolutely mid-sized. None of which is to say that the Yaris is cramped but it is a size-division smaller, so if you often carry people in the back seat or your family is growing, the RAV4 might be a bit more future-proof.

However, in driveline terms, the Yaris is the one that is truly future-proof thanks to its hybrid driveline. If most of your driving is around the city and suburbs, you might be surprised at just how efficient a modern hybrid can be. On the highway, there's less to be gained form the hybrid layout, so take that into account, too.

The other thing to consider is what happens a few years down the track at trade-in time. The RAV4 is question is already one generation older than the Yaris, and the hybrid Yaris is almost certain to be worth more as a second-hand proposition five years from now. Which means the latter will probably be the cheapest to own over that time in a wholistic sense.