It is unusual, but I have had belts slip and make no noise whatsoever. I don’t know of any direct way to check for slipping. Try making the belt tension a little tighter and see what happens.
The noise you are hearing might not be from a loose belt. It might be the belt tensioner bearings are going out. If you can’t pull on the belt and stretch it out much then it should be tight enough and the real trouble is the idler wheel bearings.
Make sure the battery and alternator connections are clean, making a snug connection, and show no signs of burning. From what you say it sounds like there is an intermittent problem with the alternator and you need to replace it.
Um AC Delco, General Motors originally. Don’t know what applications they have except tend to change all moving parts inside on a rebuild, not just test them.
@collegeboy, look at the image @texases posted. See those two black blocks inside the ring? Those are the brushes for the alternator’s stator. It is, indeed, internal, like most alternators put in cars the last 25 to 30 years. And, BTW, the alternator should not vibrate. There is something wrong with it if it does.
I have checked the alternator belt and determined its nice and tight. I also, had the alternator and battery checked again in the car. The both tested perfect. However, I still have oxygen light, charging light, and brake light on. Therefore, I am thinking pretty strongly about replacing the alternator over my Thanksgiving Break. Does anyone disagree with my though process. If so why?
" . . . I still have oxygen light, charging light, and brake light on."
If you mean that the red brake warning light stays on, that should be your first priority. Your parking brake might not be releasing. You might have a low brake fluid level. Best to get this checked out asap
As far as the “oxygen light” . . . I assume you mean the oxygen sensor light. I believe on your car it may come on at set intervals. Perhaps it’s time to replace the oxygen sensor. I’m pretty sure you just have one, by the way
FWIW . . . I don’t believe it’s possible to hook up a scanner to your car, because it’s literally pre everything. It’s even pre-OBD1. I don’t think you even have blink codes or a check engine light.
This is what the priorities would be if it was my car
- Brake light . . . assuming you mean the red brake warning light
- Charging light
- oxygen light . . . assuming you mean the oxygen sensor light
OBDI became manditory for all vehicles sold in the U.S. in 1983. If the vehicle has an O2 sensor, it’s an On Board Diagnostic vehicle.
Here’s how you pull the DTC’s from your vehicle.
Tester
I have replaced my alternator. Also, I took the alternator apart and discovered that the voltage regulator had melted. Plus the metal brushes inside were gone. So I bought and installed a new regulator.
Tester, thanks for mentioning how to test my sensors. I did not know how to do that. That is a neat tool.
Thanks, everyone else for being a big help to a young college student - with minimal car repair knowledge.
I rest my case that a shot alternator can still test good at an auto parts place. Been there.
Agreed, @Bing. After an intermittent battery light, I took my alternator out twice and had it tested at the parts store, and it passed both times. I finally broke down and took it apart to find the brushes so worn, there was hardly anything left. I put it back together and got a reman.
@Tester, ODB-I was not mandatory for post-'83 cars. ODB-I simply made sense with EFI to diagnose ECM and tuning issues. Case in point, I had a 1990 Toyota Pick-up, last year for the 2-bbl carb, and had no CEL and no O2 sensor. There was no ECM, but did have a couple of electronic modules, one for ignition and one for a pair of emissions-related vacuum solenoids and an intake manifold heater. ODB-II became mandatory in all cars in 1996.
There is an inexpensive gage you can buy that measures the tension on the belt. If the belt is shiny anywhere on the friction surfaces, cracked on the underside, readily able to be moved in & out by more than about 1/2", or more than 5 years old, change it out and consider changing the tensioner too. Parts stores can check it for you.
Having said that, and saying that you should check the belt and tensioner, usually a slipping or loose belt will first present itself as squealing when turning. The power steering pump offers more resistance than the alternator, and that’s usually how a loose belt presents first.
By the way, any parts store can test your alternator too. I’d suggest testing before changing parts.
Too late, TSM. He already replaced the alternator.
I gotta’ say, OP did pretty darned good for not knowing a wheel from an alternator, hee, hee. Good job, OP.
ok. Thanks for the additionally advice.
@collegeboy
Haven’t heard from you in awhile . . .
How’s that Sentra doing?
Thanks, NYBo, I saw that. Perhaps I should have used the past tense and said the alternator could have been tested rather than just change it. Point being, diagnose first, then change parts. Ah, the wonders of the English language.