George Bott
  This activity is a multi-week project continuing from day to day and involving both classroom work and under-the-hood experience.

  Critical thinking, Consumer education, Employability, Job skills, Life skills, Problem solving, Reading comprehension, Technology, Vocabulary development, Work environment, Writing skills

Learner Level:
  All levels.

Time Frame:
  Several class sessions

Learner Grouping:
  Individual, Small group

  My class is in an office called "WorkForce NetWork." This class is attended by four or five students and meets four hours a day for five mornings a week. Learners are a combination of those who attend voluntarily through Fresh Start and those for whom attendance is required in order to keep their welfare benefits. Attendance is still sporadic. The classroom is equipped with tables rather than individual desks.

The first session will be a presentation to the class in the classroom of the functions of the battery, alternator, and starter motor, belts, and the effect of corrosion on battery terminals/connectors. The remaining time can be spent under the hood of a car, with learners getting their hands dirty and gaining real-world experience as auto mechanics.



Type of Program:

Student Population Served:
  Select Population

"Diagnosing a car non-starting problem."

When a car won't start, or when the battery appears not to be charging, the driver often thinks a new battery or alternator is required. Neither may be the case. This activity suggests a procedure for "shade-tree mechanics" to use in diagnosing the problem. __________________________________________________________

Learning Objective:

  • Learners will observe safety procedures.
  • Learners will identify drive belts, alternator, battery, starter motor, spark plugs, spark plug wires, and cooling fan in a car.
  • Learners will gain practical experience in using wrenches, checking belts for wear, tightening drive belts, disconnecting and removing batteries, checking and/or replacing spark plug wires, and checking and/or replacing spark plugs.
  • Learners will be able to explain the function of the battery, alternator, starter motor, spark plugs, belts, and cooling fan.
  • Learners will follow written and flow-chart procedures to diagnose a car non-starting problem.
  • Learners will recognize whether or not they might be interested in auto mechanics as a career.

Primary Skill:
Learn through research

Secondary Skills:
Solve problems and make decisions, Plan, Read with understanding, Listen actively, Convey ideas in writing, Reflect and evaluate, Decision making, Lifelong learning

Learner Needs & Goals:
Most adult learners now drive cars, or will in the future. At some time(s) in their lives the car won't start, or the lights will grow dim. They have a choice of diagnosing and fixing simple problems themselves at relatively low cost or of spending the money to be towed to a garage to have the problem fixed. This activity is directed toward providing adult learners with the background and experience necessary to diagnose the most frequent problems: battery, corrosion, belts, and alternator.

Some of the learners may have an interest in becoming an auto mechanic. This activity may help them decide to do this or not.

Learning Activity Description:

My background for attempting to teach this activity is a "lifetime" of trying to maintain my own cars (not always successfully). My approach is to try to use logic (and sometimes trial and error) to identify the source of the problem. If I do take a car to a garage, I always try to debrief the mechanic who did the work to find out why it was done and what reasoning led him to do it. The idea for using Coca-Cola came to me in this way from The ED JONES TEXACO in Crossville, Tennessee. It was a complete surprise to me, but it works.

This activity will take many class sessions to accomplish. It is composed of several sections. The first section is the academic part that takes place in the classroom when I introduce the idea of working on cars and start providing background that my adult learners will need to know. The second section is actually under the hood of a car. We do not have any not-starting cars sitting in the parking lot, so we will work on one that does start (or at least it will start before we work on it.) My goal here is to get learners thinking enough about the problem, and comfortable enough with actually getting under the hood and on the end of a wrench, that they will try it themselves the next time one of their own cars does not start.

These first two sections of the learning activity are described below. The third section is only hinted at here through the handouts, and is the actual diagnostic procedure that takes place when one of their cars won't start. The learning activity has been a success if they try the diagnostic procedure on their own in an attempt to diagnose the problem when they do have a car that won't start. If experience is any guide here, they are likely to call me if they have trouble, and I will have to talk them through the procedure.

I make no claim that the diagnostic procedure presented as a handout will work in all cases, but believe it will be a good start. People who try to follow it may learn ways in which it should be modified to be more useful (or even more correct). But this is true of all of life.

Possibly some instructors will feel uncomfortable with this activity but I believe they will be rewarded with an education, a feeling of accomplishment, hopefully some money saved, and dirty hands. Very possibly there will be one or more learners in class who will be able to help teach the teacher in various ways.

Here, then, are the steps for this learning activity.

Lecture with opportunities for questions and discussion.
  1. Describe the activity and its purpose.

  2. Go through a careful discussion of WARNINGS (see below). Give each learner a copy of the safety warnings. (Handout 5)

  3. List the kinds of common problems the procedure is intended to diagnose: battery, alternator, corrosion of electrical contacts, starter motor, spark plugs and plug wires, and loose or broken belts and wires, and go into some detail on each and the consequence of each source of trouble.

  4. I would present a brief explanation of how an engine operates, and the relationship of the items in 3 above to its operation so the class understands how everything works together, and what happens when one of the items does not function correctly.

  5. Finally I will go through a detailed explanation of the flow chart along with the written diagnostic procedure so learners will understand the logic of the diagnostic process.

(Also available as Handout 5 to copy for learners)

  1. Batteries contain a highly reactive acid. Occasionally batteries explode. People working on or around batteries should always wear safety glasses.

  2. Batteries generate a highly flammable gas. People working on or near them should not smoke or do anything which would generate sparks or fire.

  3. When working on engines, wear tight fitting clothes, and keep hands and clothes well clear of belts and cooling fans. Never touch a belt or a fan when the engine is running. Some cooling fans are thermostat operated and can turn on even if the engine is not running.

  4. Bolts holding cable contacts onto batteries with side terminals screw into threads cut into lead. These threads can be stripped (and the battery ruined) if too much force is applied with a wrench. To avoid this damage, use a short wrench to remove these bolts. Notice carefully how much torque is required to remove them and do not exceed this torque when tightening the bolts WITH THE SAME WRENCH. If you find that one bolt was loose when disconnecting the cables, test the other one to determine the correct torque to use.

Demonstration with "hands-on" participation of all learners.

  1. The first step is to show how to release and raise the hood since some learners may never have done this.

  2. The second step is to identify all the parts of interest to the learners. I might use at least two cars to do this since different makes have the parts in different places, but the parts usually look similar even if in different places.

  3. Once more, I will go through a discussion of safety, and of the reason for careful recording of which spark plug wire goes to which spark plug.

  4. The next step is to see how to inspect the belts, both condition and tension. If the underside of a belt is cracked (across the belt rather than along it) it should be replaced. This leads to an actual demonstration of how to replace it and how to tension it correctly. Tension can be checked in two ways: the belt should feel tight if pulled outward; with hood and front windows open and the transmission in neutral, step sharply on the accelerator for just a moment and listen for a squeal. If you hear one, shut off the engine and tighten the belt some more. The squeal is produced by a loose belt slipping on one or more pulleys. Here each make of car will be different in detail but similar overall. Belts, spark plugs, and spark plug wires are the least expensive parts to replace so I always check them first. So here I will get out the wrenches and give each of the learners an opportunity to get dirty hands.

  5. The belt exercise will be followed by an inspection of the alternator and a discussion of how to remove it should this ever be necessary. I will not attempt to remove it since this could take longer than I would like to devote to it.

  6. After the alternator exercise has been completed, we will start on an inspection of spark plug wires and then spark plugs. We will actually remove and replace a wire or two and a plug or two so that everyone will have this experience. We will inspect the plugs to see what their condition is and how to re-gap them. I will take a new and a badly fouled plug so the class will be able to see what "bad" is. They can re-gap the fouled plug.

  7. Next we will go after the battery. The first step is to find it. On some cars this may take some investigation, but it is a reasonably large lump and has large wires running to it. As a last resort, follow the large wires to a fairly large lump which probably will be the battery. All batteries look about alike. They do differ a bit in size and shape, and whether the terminals are on the top or on a side.
  8. We will determine how to get to the battery since many now are hidden under a structural bar that must be removed to get a good look at the battery or to replace it. Once we have removed any structure above it, we can examine the wires that attach to it. With luck, on someone's car, we may even see some corrosion at the terminals and will be able to show how to remove it.

  9. We will actually remove a battery so that the class will see how this is done (and appreciate how heavy a battery is). With the battery out of the way, we should get a good view of the starter motor so the class can see what it looks like, and how wires attach to it.

  10. Then we will clean all corrosion off the battery and cable terminals using Coca-Cola (use plastic cup for Coca Cola and soak parts until bubbling stops.) Then we will re-install the battery and all structural members. We will start the car to verify that it still runs. This should complete the exercise.

DIAGNOSING A CAR NON-STARTING PROBLEM This part of the activity has to wait for the availability of a non-starting car.

Materials and Resources:

  • Copies of "Written Diagnostic Procedure" (Handout 1) for each learner
  • Copies of "Flow Chart of Diagnostic Procedures" (Handouts 2, 3, &4) for each learner
  • A plastic cup
  • A bottle or can of Coca-Cola (regular, not diet)
  • One 5/16" wrench with box end on one end and open end on the other
  • One set of socket wrenches with a 10-inch extension bar
  • One knife-edge screwdriver, and one medium Phillips-head screwdriver
  • Safety glasses for all learners
  • Two cars to work on

Attachments: (For Internet Explorer users, right click on link then choose "Save target as". For Netscape users, just hold down the shift key and click on the link.)

The instructor should observe carefully the activity under the hood as it progresses for two reasons: (1.) safety warnings absolutely must be followed at all times, and (2.) each learner must be assured a chance to handle wrenches, check belts, etc. Safety precautions and access to the experience are two of the objectives for this activity and can only be assessed by instructor observation. Part of this learning activity will not take place until one of the learners has access to or responsibility for a car that will not start. We will have discussed how to follow the narrative and flow-chart versions of the diagnostic procedures, but learners can demonstrate that they can follow written and flow-chart procedures only during the course of the work on a car that won't start.

In addition to instructor observation for assessing objectives, learners should be asked to write a report describing the function of the battery, alternator, starter motor, spark plugs, belts, and cooling fan. Learners can also be asked to correctly identify these components in a car we have not worked on.

I have none at this time. I will not undertake this activity until we have warm weather.


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