No-start

[ChevyMan]

Left home to go grocery shopping. after done shopping, I tried to start the car but nothing !!. The engine would not turn over. Checked the headlights. They work. Tried to close the electric driver window. It goes up very slowly, if at all.. Wipers don't work. Can the starter be the culprit? Have the car in the shop. Car is 76 Chevy Impala. Will check with the shop Monday morning.

Any ideas as to what happened? I'm all ears, so to speak.

Larry.

[Ken]

My initial guess would be a high resistance cell in the battery. The voltage drop across the cell will vary with the amount of current required to operate different functions. Starter - very high current virtually all volts dropped, lights work but usually dimmer than normal, wipers and window motors again high current, poor or no operation.

A dirty battery post contact will have the same effect as willl a failing link betwee the battery post and the cell pack.

FWIW, from what you have said, my main guess is a failing battery..

Ken.

[MikeHalloran]

Dead/dying battery is good first guess.
Next: corroded/missing ground cables, e.g. from body to block.
Next: rollover switch. ... Not present on a 76 Impala, I'm pretty sure.
Next: neutral start safety switch; sometimes they just fall out.

[ChevyMan]

Funny thing though, Mike. There were no indication prior to yesterday morning about a weak battery. Car started right away, as in previous days, with a flick of the ignition key. I hardly drive, though. Could that be the primary reason the battery, if that, failed. Even then, at least once a week I run the car fast enough to charge the battery. I guess I should drive it more often then ?

[ChevyMan]

Ken, I got the car back yesterday. They simply replaced the alternator and installed a new battery as you and mike suspected.

They tried to charge the battery but it wouldn't hold a charge.

[Ken]

Glad you got it fixed, Chevy. Did they say why they changed the alternator?

Ken.

[ChevyMan]

I never thought of asking why they replaced the alternator. What is the primary reason for alternators, anyhow?

[grouch]

I never thought of asking why they replaced the alternator. What is the primary reason for alternators, anyhow?

The battery starts the engine and uses part of its charge to do so. the alternator will recharge the battery and also supply extra power to run the lights, radio and so on. A weak battery can kill an alternator. A completely dead battery can put such a strain on the alternator that it burns the diode out and the alternator is shot.

[MikeHalloran]

Whenever the engine is running, the alternator generates electricity to charge the battery.

Modern 'high efficiency' (cheap to build) alternators have little margin for abuse, and often burn themselves out trying to charge a dead or dying or merely discharged battery, so you often end up replacing both, one at a time, no matter which fails first.

That wasnt a problem when your car was young, but chances are your mechanics weren't born then, so wouldn't know of a time when alternators were more robust than they are now.

I think modern mechanics change both alternator and battery at once as a matter of routine, which saves you a small bit of labor and one incident of inconvenience. ... and it saves them, and you, the time and labor cost consumed identifying the real root cause of the no-start.

[Ken]

I think modern mechanics change both alternator and battery at once as a matter of routine, which saves you a small bit of labor and one incident of inconvenience. ... and it saves them, and you, the time and labor cost consumed identifying the real root cause of the no-start.

Interesting point, Mike. Over the last sixty odd years - even when running my own servicing business - I have changed many failed batteries without any need to change the associated dynamo or alternator. That was why I asked if the shop had said why they changed the alternator.

Checking out an alternator is fairly quick and easy and I suspect that the double swap is more laziness and a means of making a quick buck than a necessity.

Ken.