The only way anyone will be able to answer this is if they have had it happen and were able to properly diagnose it. I'm hoping that someone else has experienced this. When I got home from work yesterday, a trip of about 10 miles, I noticed a very high pitched constant whine coming from the engine compartment. I couldn't accurately tell whether it was coming from the front or the rear of the engine. It sounds like a leaf blower way off in the distance. It lasted for about 5 minutes, then quit. A few moments later it began again, but at a lower volume and then just a little later quit entirely. I wish I would have thought to disconnect the battery, as it sounded like something requiring an electrical current. This happened once before, but I thought it was someone in the neighborhood using their leaf blower. My wife said it was coming from the car, but I didn't believe it was. Yesterday confirmed it though. There was no doubt that the noise was coming from my car. (1985 IROC-Z with the 305 TPI engine).

Any thoughts of what this might have been

 

Could be a vacuum leak or maybe bearings going on a pully.

 

I failed to mention in my initial post that this noise occurred after shutting the engine off

 

not sure but could it be the eletric fan turning on.....but im not sure if you got them or not, never knew much about early TPI's

 

Yes, it does have an electric fan, but it wasn't running. Operating temperatue was right at 220 when I shut it off. Never thought about that. Should probably check to ensure that it's working okay. I know if I turn the A/C on it should start right away.

 

Okay, so I open the hood to see if my mystery noise is happening again. I turn the car off, open the hood and no noise. Then all of a sudden, there it is. I'm looking all over and trying to isolate where it's coming from. Sounds like the front of the engine, possibly around the water pump. Then it stops. I start the car and then shut it off, and the noise returns. I disconnect the negative battery terminal, and the noise persists. I'm thinking it's coming from something that's under pressure. I do have what looks like dried coolant on top of the water pump, but no visible leak. I do have to add coolant once or twice a week.

 

how lomg does the noise last after shutting down and is it when the engines hot or cold also can you better describe the noise or take a video and post it up

 

Crazy question: Was the A/C running before you shut down?

 

If you have an air pump, make sure the fittings are tight.

 

2 thoughts obviously the cooling fans as mentioned earlier even if there not running if it failed it can make some strange sounds next ide check for the blower motor for cabbin heating/AC.

 

The noise lasts for a few minutes and the engine is at normal operating temperature. The sound is a constant high pitched whine. Sounds like a leaf blower would about a block away.

 

It does have an air pump and the sound does seem like it could be coming from that area. Would it be possbile for it to make that noise after the car has been shut off? I'll check the fittings anyway. Thanks

 

No, I wasn't running the A/C.

 

why dont you start unplugging **** start with your fans then blower motor(mine had a mouse in it and made a noise llike a motorcycle when it was on)

 

Well he disconnected the negative battery cable... that should instantly shut off anything electrical.

 

Pressure test your cooling system and fix the leak.