Is this sound related to a bad alternator?

Maintenance/Repairs
1

Hey all, recently there has been a loud sound coming from my engine and i think it is the alternator, it sounds like a high revving sound. It only been like this for a week or so. It’s an audi a4 b8 sline 2014
sound to the revving, loudest by alternator

2

First thing I’d check is the idler pulley(s) for the serpentine belt. How old is the belt? If it’s original I’d replace it and check the pulleys and alternator while the belt is off. If the pulleys rotate smoothly and freely then it might be the alternator.

3

So, if you think it’s alternator what are you going to do? Have shop fix it? Do it yourself? Why not remove belt and inspect all pulleys?

4

Using a mechanics stethoscope will verify if the alternator is making the noise.

image
image600×600 53.6 KB

Tester

1 Like
5

Thanks for the replies. I took it to the garage when i heard a change in the engine months ago, it was a very small whining sound, they took the belt off and checked the pulleys and they said they were all fine, last year the belt was changed as well as the water pump. this was just before i bought it.

I do plan to try and do the work myself, i havent always been mechanical, however i have recently done brakes and i do my own service. oil, filters, etc.

6

Just ordered one. i will try this out tomorrow when it comes.

1 Like
7

You ordered an alternator or a stethoscope? You can use a chunk of hose or long screw driver too. I just replaced my alternator at 150k as a pre-emptive repair. Kept the old one on the shelf if needed. Stuff seems to last a lot longer these days.

8

Just be sure that, whatever tool you use, you don’t wear a necktie or anything else dangling from your neck when you bend over a running engine.

9

Considering a new alternator is over £350 i nought the £10 stethoscope :slight_smile: And yeah, done a bit of research and dont wanna get anything caught in the pulleys ha.

1 Like
10

Remove the belt, start engine to see if noise is still there or gone, if still there then it is not serp belt related, if gone proceed with your checks…

Do not let the engine run very long without the belt on, you do not want to overheat it…

11

In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the reception of such waves and their perception by the brain

1 Like
12

Probably

I am josh