First things first: are you sure the leak is coming from the gearbox and not the engine? It can be very hard to discern the difference in a manual car, although it’s easier in an automatic as the transmission fluid is usually a red colour.

Beyond that, oil can escape from a gearbox through a variety of places. The breather could be allowing fluid out, the pan seal could be leaking, the rear gearbox seal could be faulty or you could even have a cracked transmission casing. Don’t rule out a leaking drain plug, either, as this is a very common source of a leak. You might even find the leak is coming from somewhere within the transmission cooler and its plumbing.

A powertrain warning light can be triggered for literally hundreds of reasons. So there’s no point trying to guess what’s wrong here. Instead, have the vehicle electronically scanned at a workshop and see if the on-board computer can shed any light on what components or systems are at fault.

Theoretically, the computer should have logged the cause each time the warning light has flashed on. During a scan, these faults will show up as a series of fault codes which the mechanic will be able to decipher to get a good idea of what’s wrong. Without this information, you could be chasing up blind alleys for weeks and months.

The other thing you can do is make a note of what the vehicle is doing when the light comes on. For instance, if the warning light flicks on when you’re towing, you may have a driveline overheating issue.

The steering system in your Mazda is the old-school hydraulic type, rather than the more modern electrically-assisted set-up. Noises when you turn the steering wheel often indicate a problem with the rack itself or the hydraulics, either of which can make the system grumble and rumble when you deflect it from the straight-ahead.

The first thing to check would be the hydraulic system for leaks. These will show up as drops of fluid seeping from the various joins in the system. A check of the power-steering pump's fluid level is also a good indicator of a leak somewhere; if it's down on where it should be, you have a leak. If that's the case, the whole system probably needs a once over.

You should also check the actual steering column for the source of the noise, as sometimes a simple plastic-on-plastic contact somewhere on the column or its shroud can produce a noise like this.

Within the rack itself are valves and fluid passages that can, over time trap air. When that happens, the air bubbles can make the sort of noise you're hearing, also. So before you spend any money, try this trick: Start the engine with the car stationary and then cycle the steering from full left lock to full right lock a couple of times. Often, this will bleed the air out of the system and restore things to normal. It may or may not work, but since it's free, it's worth a crack.