In the third blog posting from the local garage, our mechanic explains why it's good to know a little bit about how cars work - and to ask questions.

I'm really pleased that experienced mechanics are reading my blog and leaving feedback. But, to be honest, they're not who I'm writing for: I'm writing for the customers! And this week I want to talk about how to avoid the cowboys and conmen (and they're usually men) that can give this business a bad name.

There are some people who think you shouldn't get into a car in the first place unless you know how every little part works. I'm not one of those people. As I type this I haven't got the foggiest idea of how pushing a key makes a letter on the screen and then it gets on the Internet so you can read it.

But it's good to know the basics of how your car works, so people don't pull the wool over your eyes.

The heart of the car is the engine. It's a motor. It makes movement: like the motor in a washing machine or the motor in a food processor. The engine needs fuel, lubrication (oil to stop the hot metal parts from seizing together) and cooling. Most cars' engines are cooled with water (but the old Porsches and Volkswagens I deal with are cooled with air). It also needs an exhaust system to take away all the nasty gases.

Then you've got your transmission. These are the bits that 'transmit' the movement from the engine to the wheels: the clutch and gearbox, the propellor shaft and the final drive unit.

You've got the chassis. This is the backbone of the car, the frame. The chassis includes suspension (springs to stop the jolts you'd get if the wheels were connected directly to the frame) and steering.

Then there's the electrics. The engine needs electricity to fire the spark plugs to ignite the fuel. In turn, part of the engine's movement is used to generate more electricity to charge the battery. This keeps the spark plugs firing and powers things like your lights, interior fan and MP3 player.

And finally you've got brakes. These apply pressure to moving wheels to slow them down and stop the car.

If you know these basics, you know where in the car the problem is. Is it an engine problem? Is it a transmission problem? Is it an electrical problem?

There are some mechanics who give our industry a bad name. They size up customers by throwing in technical words. When the customer looks baffled they see pounds flash by their eyes and talk in babble. The more confused the customer looks, the more they think they can charge.

My advice is simple: if you don't understand something a mechanic says, get them to explain it, it layman's terms. Ask them to point to the bit in your car. If they're reluctant to do this, go elsewhere. A good mechanic loves engineering and is happy to share his knowledge.

The industry is still dominated by men. I don't know why it's still the case. I'm lucky that I get a lot of lady customers in my workshop but that's down to the particular cars I specialise in - Beetles and Campers are very popular with women. If you're a woman and a garage treats you patronisingly: walk away. There's no place for that kind of attitude.

Word of mouth recommendations are always good. And if your car's more than a few years old, join an owner's group. You'll get lots of advice over the internet, or through meetings, and get to meet mechanics who love working on your particular car. People who have a passion.

If you've got a newer car, the easiest option is to go to your dealer. But dealers charge top whack and standards can vary. You should still check online or, better, listen out for word-of-mouth recommendations.

Modern cars are increasingly controlled by electronic gizmos called engine management systems. When these go wrong there's faff-all a customer can do (and increasingly, faff-all anyone but a main dealer can fix). But don't let them use these gizmos as a catch-all. Ask them to explain exactly how the engine management system is causing this fault.

At the end of the day, it's better to ask dumb questions than nod your head and pretend to understand. That's the surest way to be taken for a mug.

Find a mechanic in your local area

Previously from the Blogging Mechanic

• Get it serviced!
• Getting the hump