By Mark Gittelman
In most cases, when I guess or even take an educated guess, I pay the price. Even though my educated guess comes with 24 years of hands on experience it is wrong nearly 50% of the time. This means I have just increased my diagnosis time, and wound up replacing a part that was not required.
This brings me back to the proper troubleshooting of car problems. Get a good auto repair manual and perform all the step-by-step diagnosis that the troubleshooting manual provides. When you feel like you have found the problem take the extra step and test the individual component.
For example, let's say you are diagnosing and overheating condition. Your educated guess says that you should replace the thermostat. Why not go the extra step and actually test, the operation of the thermostat by throwing it in some boiling water and observing if it opens? If the thermostat does open while it is soaking in the boiling water you know that this was not your overheating problem. Using the same example, you may feel that the electric fan motor needs to be replaced. Again, let's take the extra step and test the operation of the electric fan motor. Applying 12 V to the power side of the fan motor and grounding the negative side can test the cooling fan operation. If the fan motor kicks on and runs, you know that this is not the problem with your overheating.
The next step would be to test what turns on the cooling fan motor. In most cases, there will be a temperature switch and a fan relay that complete the circuit to the electric motor. Both the temperature switch and relay can be tested.
As you can see from the above examples, when you are troubleshooting car problems, there may be multiple answers to what is causing the problem. Just guessing, and throwing parts at the vehicle may cost you more than if you took the car into a repair center and had somebody else do the work.
The reason that we work on our own car and perform do-it-yourself auto repairs is to save money, down time on the vehicle and learn something about the troubleshooting of car problems in the process. Using the above example again, let's say that your vehicle overheating problem was a poor connection to the temperature switch that operates to cooling fan motor, which I have seen many times. If you replaced the cooling fan motor and the thermostat, you have just spent about $300 in parts and a full day's work on things that did not need to be replaced. Your overheating problem could have been solved for free with no parts by repairing the loose connection.
So to review, let’s make sure before we start the do-it-yourself car repair that we are mentally prepared to diagnose it correctly. And only replaced the parts that are needed. Saving money and repairing the car can be a very satisfying experience. Do not cheat yourself out of this euphoric feeling by throwing un needed Parts at your vehicle.
Mark R Gittelman is an ASE Certified Master Mechanic. Mark can be your friend in the auto repair business. For more free info visit his automotive information blog. Or see mark's new squidoo page that answers online auto repair questions
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