Previous dead battery

Tiny
KBVSFLW
  • MEMBER
  • 1998 MERCURY MYSTIQUE
  • 95,000 MILES
Gents: this is my sons car, and we previously jumped it, thinking the battery was dead or dying, or that there may have even been a dome light left on, etc.

Then, a new battery was purchased and installed by Walmart auto center.

Now, doesn't start again, and had to be towed to a shop.

What are the possible problems?
What are the things we should ask/tell that shop to convey we know what we're talking about?
What are the typical alternator and/or starter repair costs we should expect?

Kevin
Friday, April 12th, 2013 AT 8:05 AM

1 Reply

Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
It's almost certain the generator is not working. You can easily verify that by using an inexpensive digital voltmeter to measure the battery voltage while the engine is running. It must be between 13.75 and 14.75 volts. If it is low you can do a simple test to determine if the voltage regulator is the problem. A failed regulator and worn brushes are the two most common causes of a no-charge condition. The regulator is easy to replace and it comes with new brushes. Depending on which engine you have it can often be replaced without even removing the generator from the engine.
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Saturday, April 13th, 2013 AT 12:58 AM

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