Both these cars are well equipped, well built and have a good reputation in the trade. Which means you won’t regret buying either of them. In turn, that means that the decision will come down to whether the extra standard equipment of the Astina model outweighs the factory warranty of the SP25 GT.

The extra gear in the Astina amounted to 10-way adjustable powered front seats with a memory function, specific 18-inch alloy wheels, a sunroof, radar cruise-control, forward obstacle warning, adaptive headlights, lane departure warning and lane keeping assistance, and smart brake support. Whether you reckon that standard gear is better than a year of so of factory warranty is entirely up to you. The only problem being that when the warranty runs out, you might start to think differently about the relative value of the two cars.

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.

Refuelling is actually a pretty dangerous practise, even though it’s one that most of us do on a weekly basis. So the first thing to know is that you need to stick to all the safety requirements issued by both the car-maker and the service station you’re using, including not using mobile phones while you refuel and making sure that even a few drops of spilled fuel is washed off the car and diluted with water on the ground.

Beyond that, the Mazda 323 should have a fuel-flap release lever on the floor, down beside the front-right hand corner of the driver’s seat. If the seat is positioned for a shorter driver, you may need to slide the seat back to reveal the release lever. Then, once the lever has been pulled upwards to release the external flap, you should be able to turn the actual fuel cap anti-clockwise to remove it. But take it slowly and don’t be surprised if there’s a hissing noise as some air is sucked into the tank as you break the cap’s seal. Once you’ve refuelled, replace the cap and turn it clockwise until it clicks once and spins freely, close the fuel-flap and you’re all done. It’s also a nice idea now to zero your trip-meter so you can calculate your fuel consumption next time you fuel up (not all cars back in 2001 had trip computers).