The idea behind these guides: you should be able to finish an article and understand what the information means when you are standing at a dealership, looking under the bonnet or talking to a mechanic.

Cars have become much more complicated, but learning about them doesn't have to be difficult. You don't need to memorise every specification. Start with the few things that actually affect how the car drives, what it costs to run and what kind of maintenance it needs.

Here are some useful places to start.

First, understand horsepower and torque

These two numbers appear on almost every car specification sheet, and they are often treated as if one number tells you whether an engine is good or bad. It doesn't work that way.

Torque describes twisting force. Horsepower describes the rate at which work can be done. In a real car, the transmission, engine speed, vehicle weight and gearing all affect what you actually feel from the driver's seat.

That is why a car with a modest horsepower figure can still feel perfectly lively around town, while another car with a larger number may feel very different.

Don't choose an engine by size alone

Engine capacity is useful information, but it is only one piece of the puzzle.

A 1.0-litre turbocharged engine and a 1.5-litre naturally aspirated engine can have very different power and torque characteristics. Add the gearbox and the weight of the vehicle, and the comparison gets even more interesting.

When comparing cars, look at the whole powertrain rather than just the number printed next to “engine displacement”.

How to think about a turbo engine

A turbocharger forces more air into an engine. That lets engineers get more power from a smaller displacement.

For a driver, the result can be strong acceleration without needing a large engine. But turbo engines also create extra heat and rely heavily on proper lubrication and cooling.

If you are buying a turbo car, the useful question isn't “Are turbos good or bad?” It is “What does this particular engine require, and does that fit the way I use the car?”

City driving and highway driving are not the same

A car used for short journeys through crowded city streets has a different life from one that spends most of its time cruising on highways.

City driving means more stops, more idling, repeated acceleration and less time at steady speed. Highway driving generally gives the engine longer periods of continuous operation.

This difference can matter when you are choosing between petrol, diesel, hybrid and electric powertrains. It also matters when thinking about maintenance.

How to read a car specification sheet

Don't let a specification sheet overwhelm you. Start with a handful of numbers:

After that, look at the things that matter to your own use: fuel economy, ground clearance, boot space, service requirements, safety equipment and warranty coverage.

What should you ask before buying a used car?

A used car deserves more than a quick look at the paint.

Ask for the service history and check whether the mileage and paperwork make sense together. Start the engine when it is cold if possible. Pay attention to unusual smoke, noises, warning lights, rough idle and leaks.

Take a proper test drive. Try normal acceleration, braking, turning and reversing. If the car has an automatic gearbox, notice whether gear changes are smooth and consistent.

None of these checks proves that a car is perfect. A professional inspection is still valuable, especially when you are spending a significant amount of money.

Fuel economy: don't trust one number blindly

Official fuel-economy figures are useful for comparing vehicles under a standard test procedure, but your own result depends on how and where you drive.

Traffic, air-conditioning use, tyre pressure, driving style, vehicle load, road conditions and temperature can all change consumption.

If you want to know what a particular car costs you to run, tracking your own fuel use over several tanks is much more meaningful than judging it from one short trip.

When should a warning light worry you?

The correct response to a warning light is usually neither panic nor ignoring it.

Check the owner's manual to understand what the symbol means. If the car is driving normally, arrange diagnosis according to the manufacturer's guidance. If the warning is accompanied by overheating, severe loss of power, heavy smoke, unusual mechanical noise or another serious symptom, stop driving when it is safe and get professional help.

One useful habit is to note exactly when a problem appears. Does it happen only when the engine is cold? During acceleration? After refuelling? At idle? Those details can help a technician find the cause.

Petrol, diesel, hybrid or electric?

There isn't one powertrain that makes sense for every driver.

Petrol engines remain common and can work well for mixed or city use. Diesel can make sense for drivers who regularly cover long distances, depending on the vehicle and local requirements. Hybrids combine an engine with electric assistance and can be particularly interesting in stop-and-go driving. Electric vehicles replace the combustion engine with an electric motor and battery, bringing a different charging and ownership routine.

The important part is matching the technology to your routine rather than choosing based only on what is fashionable at the moment.

A simple way to learn about your own car

Take the owner's manual and find five things: the recommended engine oil specification, service interval, coolant information, tyre-pressure information and the meaning of the main dashboard warning lights.

That's a surprisingly good starting point.

Then open the bonnet occasionally and learn where the coolant reservoir, oil filler, dipstick if fitted, brake-fluid reservoir and battery are located. You don't have to start taking things apart. Just knowing what you are looking at makes future maintenance conversations much easier.

For exact vehicle information

Specifications, maintenance intervals and equipment vary by manufacturer, model year, engine and market. For a particular vehicle, always use the owner's manual and official service information as the final reference.

More from EngineTheoryLab

For the engineering behind modern powertrains, read Engine Technology. For everyday care, see our Maintenance guide. You can also compare German Engines with Indian Engines.