I’ve got a 1991 Buick Regal Limited with the 3800 V6. Every time I start the car, there is a loud “rattle”, which goes away after a few seconds. However, if I turn on the heater blower or even the headlights, the noise returns. Could this be noise from the alternator? (It almost sounds like something is “hitting” a piece…could something have come loose?) I’ve never known alternators to make this noise, so I’m just looking for opinions. Thank you!
Sounds like the alternator is sure triggering it.
Check the mounting bolts on the alternator and other accessories.
Tug on pulleys to check for looseness.
When a load on an alternator increases the noise, it certainly could be alternator bearings. If you haven’t used this trick, it’s certainly time you learn this and pass it on. Take a piece of hose, garden hose, vinyl hose, rubber hose, anything about 2 feet long or so. Put one end up to your ear, and hold your hand close to the other end and place it next to or on the items you wish to listen to. This trick is really slick for pin pointing bad alternator bearings, bad idler pulley bearings, you can year your fuel injectors every time they open and close clearly, etc. Be careful not to put the end of the hose or your hand near any moving parts, or you might wish you never tried it in the first place. I promise you’ll be able to distinguish alternator bearings making noise with a change in load, if that is what is causing your issue. Oh, one more thing: After you get all through, and wash your hands and clean up, go in the house and look in the mirror to ensure you don’t have a black mark on your ear that you’ll walk around with for the rest of the day.
Thank you both for the suggestions. I will check to make sure the alternator is not loose or anything, but I believe that it is probably the bearings, as suggested.
I’m assuming the bearings can be replaced by having the alternator rebuilt. Is that worth it, or should I just get a new alternator? Just curious…
If it turns out the bearings are shot, you could try to get it rebuilt. I don’t know the cost, but since you have an older GM vehicle and there are a ton of those alternators out there, the reman. alternator probably won’t cost that much. There is a place in my town that will rebuild your alternator, but you have to deal with the hassle of not getting the part back for a day or two. And I don’t know if most towns have a shop that will do that. Most of the reman alternators will last the full time you own the car, so with that mind, start looking around. Bearing noise might indicate the alternator will eventually fail, but maybe not overnight. I’ve seen people drive their car for over a year with the alternator screaming at them.
Great! Thank you again for the suggestion. I’ll check to see what I can find. I see even some parts dealers (Autozone, etc.) have remanned alternators, so that’s an alternative, too.
These forums are most helpful. Hopefully, though, I won’t need to use them again any time soon!