Symptoms of Alternator Going Bad

What are the symptoms of alternator going bad? Does it go bad gradually or suddenly? Have '90 Seville and the battery is almost 3 yrs old (w/ 5 yr warranty) and AFAIK, the alerternator is the original one. Asking because one time the engine did not start right off when the ignition key was turned on when the car was unused for like two weeks. There was a dead spot when the ignition key was first turned on, just like when you have a dead battery. But the second turn on started the engine. Been running the car almost everyday for 4-5 miles and have not experienced the dead spot problem in engne starting. But feel something's not right. Am I being paranoid?

Reply to
Zephyr
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Take a voltmeter and put it on DC volts, start your car and put the leads on the battery to see what the voltage is. It should be at least

13-14VDC with the car running. Anything lower means your alternator is bad. Anything higher is also bad too.

Alternators can go bad suddenly or gradually. It all depends. You could also have a loose wire, or corrosion on the battery causing your charging problem.

That dead spot you experienced could also be from a sticking starter relay/solenoid that could be going bad.

Reply to
m6onz5a

As a matter of fact, there are voltmeters of sorts that you can plug into the cigarette lighter/12 power socket and monitor the voltage continually. Some just come with a string of different color LEDs. These are an excellent tool.

Another symptom of an alternator problem (diodes, specifically) is a lot of noise in an AM radio when car is running. It is a whining noise.

Many alternators have the voltage regulators built in, and so an overvoltage, usually a regulator problem, could be considered an alternator problem. An undervoltage problem could be either a regulator or the alternator proper.

Reply to
Don Stauffer

It is unlikely the alternator has anything to do with what happened. The cause was most likely some combination of the battery losing it's charge and the battery cables developing corrosion during the 2 week the car sat unused. This would be even more likely if the weather was damp and rainy during the 2 weeks it sat. Before you consider replacing any parts check the battery connections to make sure they are clean, dry and tight.

-jim

Reply to
jim

(This shall serve as replies to respondents. Thanks for the responses.)

The Seville has battery voltage monitor (along with coolent temp, engine rpm and oil index). When the "problem" developed, started monitoring it closely. When the ignition is on, the voltmeter reads

14.5 initially, but then drops down to 13.5 after a few miles. Noticed voltage drop before, but do not remember dropping to 13.5. My recollection is that it used to drop to 14.1/14.2, not to 13.x.

Checked the battery terminal and cables and I don't see corrosion or loose connection.

Just got back from freeway driving (75 mph) and the voltmeter gradually crept up to 14.0 and stayed there for like 30min (and it would not go higher). But when got back into the city driving (40 mph), voltage gradually drops down to 13.5. As mentioned I don't think this was normal and that was the main cause for concern.

Hard to tell on AM radio noise as the antenna is broken. There is hissing whether engine is on or off.

Does the above give any more hints?

Reply to
Zephyr

That sounds like a dead spot on the starter, or maybe a loose connection.

Alternator electrical failures I've known are usually sudden and unambiguous, though their mechanical failures (e.g., bearings) usually develop over time, with warning signs.

An inexpensive multimeter can let you know what's going on. With the engine running, you should be seeing something around >= 14V on the battery posts, if alternator and wiring connections are good. With the engine off, the battery should read in the mid twelves.

How well the battery holds how much charge, and how willingly it delivers current, are questions for a load tester. Again. though, it isn't what I'm thinking of, for your specific symptoms.

Cheers,

--Joe

Reply to
Ad absurdum per aspera

About forty something years ago, I read somewhere that if a flat blade screwdriver will stick pretty good on the middle of the rear of an alternator, that means the alternator is good. One of those old ''Tricks''. cuhulin

Reply to
cuhulin

Yesterday and today the engine started with oomph. The freeway ride two days ago must have done some good. Will drive everyday and hopefully the problem does not reappear. Thanks again for taking the time to respond.

Reply to
Zephyr

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