Auto Repair For Dummies®, 2nd Edition


by Deanna Sclar

John O’Dell, Technical Advisor




About the Author

Deanna Sclar is also the internationally best-selling author of Buying a Car For Dummies, a money-saving guide to every aspect of car ownership including buying, selling, financing, auto insurance and claims, and more. A former contributing editor to Family Circle, Boys’ Life, Exploring, and the Los Angeles Times, her articles have appeared in Redbook, New Woman, and other national magazines.

As an automotive expert and consumer spokesperson, Deanna has appeared on more than 800 radio and TV shows, including her own segment on NBC Nightly News with Tom Brokaw; Good Morning America, Today; the Lifetime, CNN, and National Public Radio networks; and local shows in 30 major cities. Her Auto Repair For Dummies video was a National Home Video Awards finalist. She’s co-hosted Outrageous Women, a weekly TV talk show, and has produced, written, hosted, and edited several documentaries. Her “Auto Repair for Dummies” course at California State University, Northridge, drew the largest crowds ever in their continuing education program.

A life-long environmental activist, Deanna led the group that threw the first Earth Day celebration in New York City and convinced Mayor Lindsay to start the first urban recycling program. The former “Thumbs Sclar” has restored two classic cars, a truck, and three homes. An inveterate gypsy and blue-water sailor, she has crewed her way across the Pacific and Polynesia, sailed and dived Hawaii and the Great Barrier Reef, trekked alone for nine months through southeast Asia and five months through Brazil, and crossed the Atlantic in a small sailboat with a companion and a cat.

“My goal is to prove that we have control over our lives,” she says. “Whether you are working on a car or making a lifelong dream come true, it’s a do-it-yourself world. Knowing this has turned my life into a great adventure, and I want to pass the good news on to everybody else!”



For my children, Gina and Casey; and my grandchildren, Jesse, Allison, Jacob, and Kylie, who will drive the vehicles of the future.


Author’s Acknowledgments

John O’Dell, for going far beyond all expectations to provide the erudition, insight, and dedication to make sure that this edition is accurate and up-to-date. Thanks so much for always being there for me!

Rosemarie Kitchin, for the support, intelligence, leads, and loving friendship that have been mainstays in my life for over 30 years.

Dave Steventon of the Canadian Automobile Association, for your friendship and guidance through every edition of this book.

Marilyn Levak, for your generosity and skill in organizing more than five years of Internet files and newspaper clippings for this edition.

Joanne Steventon, for researching and obtaining scrap art for this book.

Don Donesley, my first automotive guru, whose classes and advice made the original edition possible. Thanks for introducing me to three of the finest things in life: cars, beer, and the Mojave Desert!

The old Thursday Evening Auto Class at “Uni High,” who shared ideas, tools, and elbow grease; served as guinea pigs; and got it all together over beer and pizza afterward.

Lindsay Lefevere, Acquisitions Editor, and Alissa Schwipps, Senior Project Editor, for their heroic efforts and sensitivity from the planning stages right through to publication. Elizabeth Rea, Senior Copy Editor, for her sharp eyes and feel for style. Tracy Barr, Editor, and Bob Freudenberger, Technical Consultant, for shepherding the book through a last-minute review. Janet Wahlfeldt and Thomas Brucker, Technical Illustrator (Precision Graphics), for simple, clear illustrations of complex automotive systems; and the entire Wiley Composition Services crew who worked so long and hard on this edition. May the Fonts be with you!

And, finally, thanks to Tweety Bird, faithful Mustang, who survived all the experiments and mistakes and grew up to be a fine car and a worthy steed; to Honeybun, my dream car come true; and to Esmerelda, my lovely Prius.


What’s So Special about Auto Repair For Dummies, 2nd Edition

This book is designed for people who think that anything technical will make their brains shut like garage doors, who sincerely care about how their vehicles affect the environment, and although they believe they can’t work on their cars themselves — and wouldn’t like it if they could — are willing to give it a try. How do I know that it will work for these reluctant readers? Because it’s written by a genuine, certified ex-Dummy who has found that, despite total ignorance and a complete lack of manual dexterity, getting personally involved with a vehicle is enjoyable, rewarding, and easy. Believe me: If I can do it, so can you!

It Is Not Written for Confirmed “Do-It-Yourselfers.” It Is for You If:

bullet You have never held a wrench.

bullet You are positive that, in your case, manual labor can lead only to disaster.

bullet You haven’t the vaguest idea of how a car works.

bullet You have failed shop or arts and crafts.

bullet You believe that if you do something wrong, your car can blow up.

To Enjoy This Book, It Would Help If:

bullet You don’t believe that working on your vehicle can possibly be fun, but you’re willing to give it a try for any reason whatsoever.

bullet You are sincerely tired of being ripped off because of your own ignorance.

Why Is That Enjoyable? Because You Will Be Delighted to Find:

bullet Cars run on principles that are as easy to understand as common sense.

bullet You can save a tremendous amount of money, extend the life of your vehicle, save on fuel, and do your bit for the environment if you know more about your car!

bullet Most of the devices on your vehicle will not hurt you unless you really go out of your way to hurt yourself.

Here’s How Auto Repair For Dummies Accomplishes These Miracles:

bullet It starts from scratch. It even shows you what a screwdriver looks like!

bullet It explains each system in simple terms before you get to work on it.

bullet It provides step-by-step instructions for even the simplest tasks.

bullet It tells you exactly what you need and how to know if you’ve been given the wrong part, the wrong diagnosis, or an outrageous estimate.

It Tells You the Truth About:

bullet What makes your vehicle go (and how and why as well)

bullet How the car you drive, how you drive it and maintain it, and how you recycle or dispose of used parts and toxic fluids affect fuel economy and global warming

bullet The easy work involved in keeping your vehicle well maintained and running efficiently, and how to tell what’s wrong if trouble strikes

bullet How 15 minutes of “preventive medicine” avoids breakdowns

bullet Whether you can handle a problem yourself, and how to get it fixed at a fair price if you can’t

bullet How to extend the life of your vehicle; keep it clean and healthy; and repair the minor dents and dings it acquires on the road

These Features Will Make Life Even Easier:

bullet A Practical Glossary of Automotive Terms that are in special type throughout the book so that you can refresh your memory if you’ve forgotten what something means

bullet A detailed Index where you can look up a part, a problem, a symptom, or a specific job and find the page you need

bullet A Maintenance Record so you can keep track of what you’ve done and when you did it

bullet A Specifications Record for the data you need to buy the right parts

bullet Tons of illustrations that show you how things look and where they are

This Revised Edition Also Tells You:

bullet About alternatively fueled vehicles and other innovations so you can choose a safe and efficient vehicle when Old Faithful finally heads for the Used Car Lot in the Sky

You Have a Few Things to Supply, Too!

bullet You have to buy the book . . . and read it!

bullet You have to try to do one small, easy job yourself (you can pick the job).

There Are Fringe Benefits, Too!

bullet Your vehicle will run better and live longer.

bullet Automotive technicians will respect you.

bullet You’ll have more money to spend on other things.

bullet You’ll no longer be a Dummy!


Publisher’s Acknowledgments

We’re proud of this book; please send us your comments through our Dummies online registration form located at

Some of the people who helped bring this book to market include the following:

Acquisitions, Editorial, and Media Development

Senior Project Editor: Alissa Schwipps

(Previous Edition: Pamela Mourouzis)

Acquisitions Editor: Lindsay Lefevere

Senior Copy Editor: Elizabeth Rea

(Previous Edition: Wendy Hatch, Tamara Castleman)

Editorial Program Coordinator: Erin Calligan Mooney

Technical Editor: Karen Greenberg

Technical Consultants: Bob Freudenberger, Ken Lavacot (, Eric Pazer

Senior Editorial Manager: Jennifer Ehrlich

Editorial Assistants: Joe Niesen, David Lutton

Cover Photo: ” Bill Grove

Cartoons: Rich Tennant (

Composition Services

Project Coordinator: Bill Ramsey

Layout and Graphics: Karl Brandt, Joni Burns, Shawn Frazier, Stephanie D. Jumper, Rashell Smith, Julie Trippetti

Special Art: Precision Graphics

Proofreaders: Laura Albert, Dwight Ramsey, Shannon Ramsey

Indexer: Carol A. Burbo

Special Help: Alicia B. South, Joanne Steventon

Publishing and Editorial for Consumer Dummies

Diane Graves Steele, Vice President and Publisher, Consumer Dummies

Joyce Pepple, Acquisitions Director, Consumer Dummies

Kristin A. Cocks, Product Development Director, Consumer Dummies

Michael Spring, Vice President and Publisher, Travel

Kelly Regan, Editorial Director, Travel

Publishing for Technology Dummies

Andy Cummings, Vice President and Publisher, Dummies Technology/General User

Composition Services

Gerry Fahey, Vice President of Production Services

Debbie Stailey, Director of Composition Services




About This Book

How IBecame Intimately Involved with My Car, and Why You Should Too

Conventions Used in This Book

How I Picture You

How This Book Is Organized

Icons Used in This Book

Where to Go from Here

Part I : Getting to Know Your Vehicle

Chapter 1: Things Every Driver Should Know

Before You Tackle Any Job

How to Fill ’Er Up Yourself

How to Open the Hood

How to Take Anything Apart — and Get It Back Together Again

How to Use a Jack Safely

How to Change a Tire

How to Get In When You’re Locked Out

Chapter 2: Preventive Maintenance: A Monthly Under-the-Hood Check

Getting Your Bearings under the Hood

Check the Air Filter

Check the Accessory Belts

Check the Battery

Check the Coolant

Check the Hoses

Check the Dipsticks

Check the Brake Fluid

Check the Wiring

Check the Windshield Washer Fluid

Check and Replace Windshield Wipers

Check the Tires

Drive and Enjoy!

Chapter 3: The Way to Your Car’s Heart Is through Your Toolbox

Shopping for Tools






Work Lights


Jack Stands


Fire Extinguishers


More Things to Carry in Your Vehicle

Chapter 4: What Makes It Go? The Inner Secrets of Your Car Revealed!

Keeping Your Owner’s Manual Handy

Introducing the Engine Control Unit (ECU)

What Makes Your Vehicle Start?

What Makes Your Vehicle Run?

What Makes Your Vehicle Stop?

Part II : Powering Up with Air, Fuel, and Fire

Chapter 5: The Electrical System: Your Car’s Spark of Life

Introducing the Engine Control Unit (ECU)

The Starting System

The Charging System

The Ignition System

Warning Lights and Malfunction Indicator Lights (MIL)

Other Electrical Gadgets

Chapter 6: Keeping Your Electrical System in Tune

Determining Whether Your Vehicle Needs a Tune-up

Changing Your Spark Plugs

Replacing a Battery

Changing Fuses

Dealing with Headlights and Directional Signals

Chapter 7: The Traditional Fuel System: The Heart and Lungs of Your Car

Basic Fuel System Components

Following Fuel through the Fuel Injectors

The Engine Block: Where the Fuel System and Ignition System Meet

Supercharging with Turbochargers

The Exhaust System

Chapter 8: Keeping Your Fuel System in Tune

Maintaining Your Air Filter

Replacing a Fuel Filter

Servicing the PCV Valve

Troubleshooting Catalytic Converters

Checking the Compression in the Cylinders

What to Do When All Else Fails

Chapter 9: Diesels For Dummies

Clean Diesels: Nontoxic Newcomers

The Pros and Cons of Diesels

What Makes It Go?

The Fuel System

The Electrical System

The Emissions System

Caring for Your Diesel

Getting Started on a Frosty Morning

Finding a Reliable Diesel Mechanic

Chapter 10: From Horses to Hybrids: Alternatively Powered Vehicles


Flex-fuel Vehicles


Electric Vehicles (EV)

Hydrogen and Fuel Cell Vehicles

Natural Gas Vehicles (NGV)

Part III : Staying Cool and In Control

Chapter 11: The Cooling System Up Close


The Radiator

The Fan

The Water Pump

The Thermostat

The Heater Core

The Transmission Cooler

Air Conditioning

Chapter 12: Keeping Your Car from Getting Heartburn

Overcoming Overheating

Checking and Adding Liquid to Your Cooling System

Flushing Your System and Changing Your Coolant

Finding Leaks in the Cooling System

Buying and Replacing Hoses and Hose Clamps

Repairing Leaks in the Cooling System

Adjusting and Replacing Accessory Belts

Replacing Your Thermostat

Servicing Air Conditioners

Chapter 13: Oil: Keeping Your Car Young and Happy

How Oil Benefits Your Vehicle

What You Should Know about Oil

Choosing the Right Oil for Your Vehicle

How Often You Should Change Your Oil

How to Change Your Oil Yourself

Chapter 14: It’s the Brakes!

Brake System Basics

Drum Brakes

Disc Brakes

The Parking Brake

Anti-Lock Braking Systems (ABS)

Other Electronic Braking Systems

Chapter 15: Be a Buddy to Your Brakes and Bearings

Checking Your Brake System

Getting at Your Brakes

Checking and Packing Wheel Bearings

Flushing and Changing Brake Fluid

Bleeding Your Brakes

Adjusting Your Parking Brake

Checking Anti-Lock Brakes

Part IV : Smoothing the Ride: Steering and Suspension, Tires and Transmissions

Chapter 16: Steering and Suspension Systems Smooth the Way

The Steering System

Suspension Systems

Chapter 17: How to Keep Your Car from Getting Sore Feet: Tires, Alignment, and Balancing

Tire Construction

The Secrets on Your Sidewalls, Revealed!

Types of Tires

Specialized Tire Systems

Tips for Buying Tires

Caring for Your Tires

Dealing with Defective Tires

Chapter 18: Take the Drive Train: Understanding and Maintaining Your Transmission without Losing Your Mind

The Drive Train

How Power Flows through the Drive Train

Manual Transmissions

Automatic Transmissions

Troubleshooting Your Drive Train

Taking Care of Your Clutch

Undertaking Transmission Repairs Wisely

How to Keep from Driving Your Transmission Crazy

Part V : Staying Safe and Dealing with Emergencies

Chapter 19: Staying Safe on the Road

Air Bags

Side Impact Protection Systems (SIPS)

Adjustable Devices

Child Safety Seats and Booster Seats

Smart Seat Belts

“Eyes” in the Back of Your Vehicle

Brake-Shift Interlocks

Traction Control Systems (TCS)

Electronic Stability Control (ESC)

Rollover Stability Control (RSC)

Adaptive Cruise Control (ACC)

Telematics: How Cars Communicate

Chapter 20: Troubleshooting Leaks, Squeaks, Smells, and Strange Sensations


Squeaks, Rattles, and Vibrations




Strange Sensations

Directional Signals

Chapter 21: What to Do If Your Car Drops Dead or Won’t Start

Getting Off the Road Safely

Troubleshooting the Problem

Handling a Vehicle That Overheats on a Hot Day

Overheating When It Isn’t Hot Outside

If Your Vehicle Won’t Start

Chapter 22: When All Else Fails: Finding and Dealing with a Good Mechanic

Choosing a Service Facility

Finding a Reliable Service Facility

Evaluating a Facility

Getting the Best Possible Deal

Complaining Effectively

Part VI : Helping Your Vehicle Look Its Best

Chapter 23: Keeping Your Vehicle Clean and Beautiful

Environmentally Safe Ways to Clean Your Vehicle

Cleaning the Exterior

Cleaning under the Hood

Cleaning the Interior

Remembering Those Final Touches

Chapter 24: Bodywork: Getting Rid of Dings, Dents, and Other Hard Knocks

Getting Rid of Rust

Removing Small Dents and Dings

Filling Small Dents and Holes

Touching Up Your Paint Job

Installing New Weatherstripping or Patching the Old

Dealing with Damaged Windshields

Turning to the Pros for Larger Repairs

Part VII : The Part of Tens

Chapter 25: The Ten Most Important Preventive Maintenance Measures

Change the Oil Frequently and Regularly

Do a Monthly Under-the-Hood Check

Check the Tire Inflation and Alignment

Keep the Interior Clean

Wash the Vehicle Frequently and Keep It Out of the Sun

Get Rid of Rust

Change the Filters

Change the Coolant

Lubricate the Moving and Rubber Parts

Get Scheduled Maintenance to Keep Warranties Valid

Chapter 26: Ten “Eco-Logical” Ways to Save Fuel

Take a Look under the Hood

Start Up without Warming Up

Drive Eco-Logically

Structure Trips to Save Fuel

Fill ’Er Up Eco-Logically

Keep Your Side Windows Shut and the AC Turned Off

Keep Your Tires Properly Inflated

Clean Out the Junk

Keep Your Vehicle Waxed

Use a Trailer Instead of a Roof Rack

Appendix A: A Practical Glossary of Automotive Terms

Appendix B: Specifications and Maintenance Records

Specifications Record

Maintenance Record