i30 Owners Club

GOT PROBLEMS OR ISSUES? => PETROL => Topic started by: PowderedToastMan on December 29, 2023, 03:59:10

Title: High pitch noise after turning on A/C when hot
Post by: PowderedToastMan on December 29, 2023, 03:59:10

Hi All,

Whenever it's hot out and I turn my A/C on, this high pitch noise eventually starts and will not go away until after the car cools down. Turning the A/C off does not stop it.

This first occurred last summer then went away as the weather cooled. Now that it's heating back up its happening again.

As far as I can tell the sound is originating from under the car and not the engine bay.

Hoping someone has an idea what the issue may be and appreciate the help.

Video of noise: https://youtu.be/twGKCiI4_j8?si=dRgPrq_H-Ub-QScb (https://youtu.be/twGKCiI4_j8?si=dRgPrq_H-Ub-QScb)

Title: Re: High pitch noise after turning on A/C when hot
Post by: PowderedToastMan on December 30, 2023, 02:35:32

Update: Noise appears to be coming from the exhaust and is not related to the A/C being turned on as I first thought.

Not sure how well it can be viewed in this video but the exhaust is vibrating and making that noise as far as I can tell.

https://youtu.be/ydc8745mdco?si=0xD5q7EBWK_fJaSM (https://youtu.be/ydc8745mdco?si=0xD5q7EBWK_fJaSM)

Title: Re: High pitch noise after turning on A/C when hot
Post by: PowderedToastMan on December 30, 2023, 07:30:11

Second update: the noise stops when turning the steering wheel to a certain point right, discovered this going around a round about.

I was able to reproduce this a few times. Tried to replicate this with the vehicle stationary and turning the steering wheel but it didn't work.

I now have even less idea what the issue is.

Title: Re: High pitch noise after turning on A/C when hot
Post by: Greyhound on December 31, 2023, 13:29:27

Quote from: PowderedToastMan on December 30, 2023, 07:30:11

the noise stops when turning the steering wheel to a certain point right, discovered this going around a round about.

Maybe noise stopped as exhaust (or whatever it is) causing that noise swung to the left and the noise was dampened.
Have you had a gentle prod of the exhaust with a piece of wood (don't burn your fingers) to see if moving it slightly, stops the noise.
It is a very strange noise for an exhaust to make as it does not equate to the engine revs, or does it above idle?

Title: Re: High pitch noise after turning on A/C when hot
Post by: PowderedToastMan on January 02, 2024, 05:59:35

It's not impacted by revving or idling. I tried holding the exhaust in different places with wood as suggested and the noise didn't go away, so I'm likely off on thinking that's the issue.

I drove for an hour yesterday before the noise kicked in again and this time turning the wheel made no change.

Title: Re: High pitch noise after turning on A/C when hot
Post by: PGN I30 on January 02, 2024, 10:54:45

Have you tried pulling the dipstick out while the engine is running?

Title: Re: High pitch noise after turning on A/C when hot
Post by: PowderedToastMan on January 03, 2024, 01:59:30

I haven't but I'll give it a go.

The car just stalled, it's an auto, pulling out of my drive just now. This was after having been driven this morning.

I know nothing about cars but some googling tells me it could be vacuum leak.