Today as I was driving home, I kept hearing this high pitched noise coming from my engine bay. It was happening whenever I was changing gear, so I thought it must something to do with the clutch cylinder. I then found I could replicate the noise whenever I press the throttle and then let off. This noise isn't coming from the air box but it could be something to do with the acv valve. I don't have the air pump anymore so I don't know what the hell this thing is. I'll upload a video and post it here when I can. Thanks guys

EDIT: Here's the link to the youtube video. If its not available just check back later when its finished processing.

 

Did you check the condition/tightness of the belts?

 

Both the AC and Alternator belts are brand new <800 miles and are tight. It doesn't sound like them. I know what a squeaky belt sounds like. Its much higher pitched than that of a belt.

 

Could be alternator bearing going bad. Doesn't sound like a belt

 

I honestly have no idea what that is or what it does. lol. But you could be right. The sound does seem to be coming right from the alternator or just below it around the front of the engine. Is it bad to continue driving it? Will that do it harm?

 

Spray some lube where you think its coming from. If it goes away, you know your problem.

If not, dig deeper!

Try to get past the pulleys and into the bearings.

 

You might want to remove your belts one at a time and see if you can isolate the noise.
Also take note if it happens when the engine is hot or cold or both.
Water pump bearing - any weeping from the hole?
PS tensioner pulley?
Just some ideas for you.

 

Also, if you notice, the video - the sound is when you let off the throttle or when tension is released. it is not coming on when you are accelerating.

Check tension on all your belts. If that doesn't do it, then my guess is a bearing in either water pump, power steering (if equipped), smog pump, or alternator.

As I suggested, I would remove one belt at a time to see if you can identify what is bearing is being driven that causes the noise.

 

Pilot Bearing?

 

Well, today after driving it to school and back, the sound has completely gone away and is back to normal. I am so damn confused as to why it happened just yesterday. But thanks for the feedback. I'll update this again if the sound comes back.

 

That's the automatic repair feature, it came standard in the 84 and 85 GSLs and SEs. You gotta love these 1st gens.

 

that is the fan inside the alternator touching the housing...replace the alternator. just did it