Under the Bonnet / Hood of your Car

Have you ever wondered what goes on under the bonnet of your Car.

Yes it can make a bit of noise and even sometimes rattle a bit when its not supposed to so lets take a look see whats going on.

The obvious main component under there is of course your Engine, this is the main unit with all sorts of other bits bolted on.

You may not recognize this

as it looks a lot different under the bonnet of a Car, you normally can only see the top of the engine, well that is unless you remove some covers and dig a little deeper.

The engine in the image is a Corvette but to be honest now a days they all look very similar with the top plastic covers and bits bolted on.

Without getting to technical the engine is the main component that drives the gearbox then the Gearbox provides the drive to the drive shafts and wheels, then all you have to do is either speed things up or slow them down.  If you ever hear someone mention the "drive train" of your Car they are referring to your Gearbox and all the bits in between that finally connects to your wheels, here's a couple of basic systems..

OK back to the Engine and the bits bolted on, Lets start with the "Starter Motor" as this seems appropriate, the starter motor is an electrical and mechanical component that spins the engine until it can run under its own steam, not literally tho as you'l struggle to find a steam driven Car these days.

When you turn the Ignition key to start your Car what your actually doing is powering up the "Starter Motor" and its this that cranks the engine.

The starter motor can be difficult to see on the engine as its usually tucked away down the back, common faults are jamming / sticking starters or completely burned out, you may hear just a clicking sound when you turn the key but the starter wont kick into action. (garage job usually).

Another main component is the Alternator, this is the unit that is driven by a belt usually at the front of the engine and is there to re charge the Cars Battery and therefor keep all the electrical bits working correctly.

You may be able to start your Engine a few times until your Battery runs low on power, this is because as you run your Engine and electrical components with a failed Alternator your Battery will gradually run low on power and give up the ghost.

Now how about keeping the engine cool, well most Cars have water cooled systems, with a "Water Pump" to circulate the water through the engine and cooling system, water pipes, radiator etc.  Water pumps are either driven by the same belt as the Alternator or are more built in and driven by the Cam Belt. Needless to say if your Water Pump fails the Engine will overheat and if not rectified can cause extensive damage. 

I have mentioned Belts a few times now so lets see how they look on the Engine, this image is a typical example

If your belt snaps you can lose Alternator drive, power steering, Air Con and Water pump all at once, many vehicles have a separate belt for power steering for safety reasons.

Here's another belt configuration 

Ok folks that's all for now.