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How A Car Works


The following is a brief course in how a car works.
It is well worth the reading before you get into the "HOW-TO" Instructions pertaining to specific maintenance and repair jobs.

Knowing how your car runs can make the difference between a fair repair and a royal ripoff.
Mechanics have been known to take advantage of a customer's lack of knowledge, inventing expensive solutions where there is no problem.
Finding a qualified and honest mechanic doesn't require luck,
it requires a basic understanding of how cars run.

This section of
FUNdamentals of Auto Maintenance & Repairs
explains what each system does, what its component parts are called, where to look for them in your car, and how they relate to one another to make the vehicle run.
Don't worry about what model you own; every vehicle with an internal combustion engine works on the same principles.

 By observing your vehicle as a series of simple systems,
each with a specific job to do,
it may not seem as scary as a dismaying collection of wires, hoses, and gadgets.

Once you've gotten a general idea of how things work, we will explore each system in detail.
Then when you've become familiar with how a system functions,
it will make "The How To Sections" alot more understandable!

Every car manufacturer makes sure to do things a little bit differently than their competitors do in order to get patents and say that their vehicles are the best.
 Also, the location and looks of the engine and transmission in rear-engine cars and front-wheel drive vehicles are different from those with traditional front engines and rear-wheel drive.
Therefore, if any part of your vehicle is not exactly where it is in the pictures on this site,
don't panic!
Believe me, the part is in there someplace, or your car wouldn't go.
 If you have trouble finding something, your owner's manual
(which all seemed like a foreign language to you
until you came across this Site)
 should have a diagram
showing the location of each principal part.
You could also ask a friend who has a similar vehicle, or your friendly automotive technician, to point out these "missing" parts. However, I'm pretty sure, that if you read this section carefully with an eye on your own vehicle, you can locate almost all the parts yourself.

It is always a good idea to have both an owner's manual and a service manual (Chilton and Haynes are your best bets) for every vehicle you own.

What is the difference between an Owners Manual and a Service Manual?

Owners Manual is factory printed literature that comes with All new vehicles which is specific to that car or truck

Service Manual is literature which can be purchased that is specific to your make and model vehicle

If you don't have an owner's manual, ask your car dealer if they can get one for you or if they can tell you where you can get one. Service manuals are also available for every vehicle, and I strongly suggest that you get one of these as well. Every auto repair facility cannot stock a service manual for each year, make, and model of every vehicle, and if you lend your service manual to an independent service facility that is working on your car, you can save money by reducing the time it would take them to figure out the proper way to repair it. Also, if you get to the point where you want to do more than basic repairs, one of these manuals will be indispensable. The drawings in service manuals show you where every little nut and washer fits so that you won't end up with a couple of "extra" parts at the end of the job,

and they show you how to do each job in the most efficient manner.

You can obtain a service manual at the parts department of your local dealership, or write to the company that made your vehicle and print "Service Manuals" on the envelope.
The car manufacturer will be very happy to sell you one.
If you have an older vehicle, you can find new or used service manuals or instruction books for it in bookstores.
 Public libraries often have surprisingly large collections of service manuals, too.

To find the page on which instructions for a repair job appear within this site,
look in the table of Contents found in the left hand column of each page,
the individual table of Contents which precedes each chapter located below the TITLE of each Page,
or the ‘SITEMAP of This Site.
You may at times encounter an unfamiliar term within this Site and more than likely it will be a term that I placed a link to describe it.
 . . . motion of the piston into the rotary motion of the crankshaft.
Crankshaft is highlighted with a link - Click It.

NOTE: You can always come back RIGHT where you were by clicking the  icon on your right of each page.
Included in this Site is a Glossary of automotive terms, if you want to learn the meaning of a technical word in non technical language.

What Makes A Vehicle Start?

Some people like to think that vehicles are totally powered by gasoline,
and parts such as the radio, headlights, clock, and so on - actually function on electricity,
but did you know that it also takes electricity to get your vehicle to start?

An ignition system works in conjunction with your car's electrical system to provide the power that allows your starter to make your engine turn over.
Once your engine turns over, it can begin to run on gasoline,
just as you expected it to.

The following is an in-depth explanation of what happens when you start a car.

Most vehicles still have traditional gasoline-powered engines; 
if yours doesn't,
 you can find information about alternatively powered vehicles here. 

1.When you turn the key in your car's ignition switch to Start, you close a circuit that allows the current to pass from your battery to your starter via the starter solenoid switch.


2.The starter makes the engine turn over 
(that's the roaring sound you hear before the engine starts running smoothly).
 In the section of this site titled The Electrical System tells you exactly how it does this.

3.Once the engine is running, (gasoline) fuel flows from the fuel tank at the rear of the car, through the fuel lines, to the fuel pump under the hood.

The section of this site titled The Fuel System explores it in detail, and shows you how to keep it in tune.

4.The fuel pump pumps the gasoline through a fuel filter into the intake manifold.
(In carbureted cars, the gasoline is pumped into the carburetor, but nearly everything else is similar in cars with fuel injection.)

5.Each pound of fuel is mixed with 15 pounds of air to form a vaporized mixture, like a mist. Because fuel is much heavier than air, this mixture works out to something like 1 part of fuel to 9,000 parts of air, by volume. In other words, your engine really runs on air, with a little fuel to help it!

6.This fuel/air mixture (above #5) passes into the cylinders in your engine. A cylinder is a hollow pipe with one open end and one closed end. Inside each cylinder is a piston, which fits very snugly and moves up and down.

The piston moves up, trapping the fuel/air mixture in the upper part of the cylinder and compressing it into a very small space.

7.A spark from a spark plug ignites the fuel/air mixture, causing an explosion.

8.The explosion forces the piston back down again, with more power than it went up with.

9.Attached to the bottom of the piston is a connecting rod, which is attached to a crankshaft, which leads, eventually, to the drive wheels of your car. As the piston and the connecting rod go up and down, they cause the crankshaft to turn.
 This is pretty much the same motion you use to pedal a bike:

 Your knee goes up and down while your foot pedals 'round and 'round.

10.At the other end of the crankshaft is a box of gears called the transmission.
If your car has a conventional engine with rear-wheel drive,
the transmission is under the front seat. 

If it has a transverse engine and front-wheel drive,
 the transmission is under the hood of the car.
On rear-engine cars, both the engine and the transmission are under the rear deck lid, where the trunk would ordinarily be found.

11.If your car has a manual transmission, you'll also find the clutch located between the crankshaft and the transmission. The clutch tells the transmission when to connect or disconnect the engine from the rest of the drive train.
In a car with an automatic transmission, this is done automatically.

12.When you shift into Drive
(or First, if you have a manual transmission),
a set of gears causes the rest of the crankshaft 
(which is called the drive-shaft after it leaves the transmission)
to turn at a particular speed.

13.The driveshaft runs to the rear wheels of conventional rear-wheel-driven vehicles and ends in another set of gears called the differential. The differential turns the power of the engine and the transmission 90 degrees into the axles that connect the drive wheels of the car. Because on most vehicles, the axle is set at right angles to the driveshaft, you can see that the differential is really changing the direction of the power so that the drive wheels can turn. You can see more on drive trains and transmissions in detail in the Transmission Section of this Site

Cars with front-wheel drive or with rear engines do not require driveshafts because the power source is located right between the wheels that are going to drive the car. On these vehicles, the transmission and the differential are combined into a single unit called the transaxle, which connects directly to provide power to the drive wheels.

14. The drive wheels turn and push the vehicle forward or backward, and off you go.

Let's Move On to The Engine . . .

Click the arrow above to go back where you just linked from

The objective of this Web Page is to familiarize you with basic auto maintenance
-  in some common emergencies -
not to make you an expert in auto mechanics

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 I am in no way, shape, or form telling you to do this yourself. Your results may vary. If something goes wrong, it is not my fault!
These are just guidelines.