Intermittent Radio & Power Surge

[mziggy16]

A few days ago while driving to work (~10 min commute) my radio began to intermittently cut in and out of power.

The next drive was normal with the radio operating properly.

Today, while grabbing lunch, the radio didn't have power. I sat in my car for a bit and noticed that the AC blower would surge in power followed by the radio turning back on and then losing power again a few minutes later. This happened 3 more times over 5 minutes time.

My initial thought is the alternator, but want to poll the audience before I dive in.

Thank you for any help.

[mziggy16]

Additional Evidence from the drive home from work:

The car has been taking an extra crank and the most recent crank felt a little weak.

The radio remained off the whole ride home.

I put the multimeter on it and the initial reading was 8-9v and then it quickly surged back to:

11.8 at idle
12.2 at 2k RPM
11.5 when the car was off

I drove it around some more and it remained on the entire time with no issues.

[SpyderMike]

Yes, those voltage numbers are low...by about 1+ volt. I think you are on the right track.

[John W.]

Those voltages are indeed too low. Either a bad ground, check the strap under the engine or it’s time to rebuild the alternator/ bushes, bearings and check regulator.

[mziggy16]

A little bit more evidence that should confirm it:

9.6v on crank

Had the battery tested at my FLAPS:
Rated 760 CCA, measured 567CCA
11.63V
Battery is good but not fully charged.

Of course the issue hasn’t presented itself in the past few drives, but seems like the alternator is the culprit here.

[mziggy16]

Originally Posted by John W.

Those voltages are indeed too low. Either a bad ground, check the strap under the engine or it’s time to rebuild the alternator/ bushes, bearings and check regulator.

Ground strap looks okay. It was cleaned and re-snugged last summer as well.

[917_Langheck]

Faulty voltage regulator.

Had similar issues with the seatbelt buzzer going off while engaged. Then headlights began to brighten and dim and that was the most recognizable tell tail.

Others have report other electrical components cycling on or off weirdly and usually it's a bad VR.

[mziggy16]

Originally Posted by 917_Langheck

Faulty voltage regulator.

Had similar issues with the seatbelt buzzer going off while engaged. Then headlights began to brighten and dim and that was the most recognizable tell tail.

Others have report other electrical components cycling on or off weirdly and usually it's a bad VR.

Interesting.

The only other strange thing was that my reverse lights randomly stayed on after a drive. They turned off after I restarted the car and put it in gear.

How do I tell if this if the culprit vs the entire alternator?

[pmax]

Get one of these to monitor the voltage as you drive.

Should be 14V or thereabouts for anything above 2K or so, from what I recall, don't quote me on this !

[John W.]

Yep, voltage should be between 13.5 and 14.5V at or above 2k rpm. Higher than 14.5 indicates a regulator issue. Below 13.5 indicates an alternator issue.

[930cabman]

Originally Posted by pmax

Get one of these to monitor the voltage as you drive.

Should be 14V or thereabouts for anything above 2K or so, from what I recall, don't quote me on this !

These are a cheap and effective tool. Voltage should be 13.5 - 14.5 when running 2-3 k rpms

[PeteKz]

Be sure to check them against a quality voltmeter, such as a Fluke. I have several of these that are a volt off. Then recheck them a few times to be sure they didn't drift.

[mziggy16]

Just went for a drive with one of those digital voltage gauges and got two more pieces of evidence:

1. Readings were consistently in the 11’s and no higher than 12.4, including under load and on the highway.

2. Twice at higher RPMs there was a high-pitched whine from the rear, which, given all the other evidence, seems to be bearing wear on the alternator.

Any additional thoughts?

Next steps are to call and see about a local rebuilt or maybe just buy a Bosch reman unit from our host, unless the braintrust guides me otherwise.

Thank you for all of the input so far.

[John W.]

I’m pretty sure you have an alternator issue. Look for a shop that can rebuild yours. The high pitched whine sounds like bad bearings and the low voltage is worn bushes. I got mine rebuilt recently for about $100.

[PeteKz]

Yep. Pull it and take it to an alternator/starter/motor shop