Depending on what sort of noise the transmission is making, this sounds like a broken or worn out clutch. Without a properly functioning clutch, gears can be extremely difficult to select and can also cause horrible graunching, grinding noises when trying to select any gear, but particularly reverse.

If this is, indeed, the problem, you could be looking at thousands of dollars to remove the transmission, replace the clutch and reassemble the driveline. You might even find that the engine's flywheel is also beyond saving and needs replacing, too.

On the other hand, the lazy clutch could be a simple case of a leaking or worn clutch slave or master cylinder or even a poorly adjusted clutch system which is allowing the clutch to disobey what the clutch pedal is telling it to do. If that's the case, the fix could be quite simple and relatively cheap.

The point is that you need to know what the problem is before handing over the money, because the value of the same car with either problem will be vastly different. Perhaps finding a car with a properly working clutch and driveline is a better option.

The Trophy version of the i30 used exclusively the two-litre petrol engine. As such, it actually has both a timing belt and a timing chain. The engine has twin overhead camshafts, but only the exhaust camshaft is driven by the timing belt from the crankshaft. A short timing chain then takes drive from the exhaust camshaft to the intake camshaft. The engine also features variable valve timing.

The good news is that you really only have to periodically replace the timing belt (the chain should be maintenance-free for the life of the engine). The recommended replacement interval is every 100,000km.

This needs to be fixed fast, Toni, as a car’s exhaust fumes are a deadly cocktail of gasses. Enough exposure to them can make you pass out (an obvious problem when you’re driving) or worse. Diesel engines are generally a bit smellier than a petrol engine, but no exhaust fumes should ever enter the car.

You’re either getting fumes drawn into the car via a faulty seal that is allowing exhaust fumes in, or the smell you’re experiencing is fumes in the engine-bay coming through the firewall. You need to inspect all the rubber seals around the doors and hatchback and search underneath the car and in the engine bay for a split or missing rubber bung or grommet that is letting the outside in.

The other question I have is whether the smell is the result of exhaust fumes or, in fact, the smell of unburnt diesel fuel. Diesel cars often acquire a diesel-fuel smell over time and the cause is hard to avoid. Because diesel doesn’t evaporate, the ground around the diesel pump at a service station is usually one big oily, diesel slick. When you fill your car, you unavoidably stand in this slick which is then transferred to the car’s carpet when you get back in. It’s not as crazy as it sounds, and it may be the clue you’re missing to explain the smell.