Hey all!
I did a search but didn't find results.

Our '05 Sonata (V6 - ~63k miles) has occassionally made a high pitched whistle after driving. It seems to do it on a drive after a hot day and seems to come from the passenger side in the engine compartment. Due to the location of the sound, I'm wondering if it has something to do with the air conditioning system.

It's difficult to describe. It's fairly loud. It can start doing it after the car has been sitting for some time (cooling down) and will continue to do it whether the car is running/off, AC is running/off. The pitch of the noise can vary and the length of time it does it is several minutes (+15mins). There doesn't appear to be any driveability issues, but it's concerning.

We initially thought it was coming from a refridgerator that is close by in the garage. I thought the 'fridge compressor might be bleeding off or leaking, but I found out it was actually coming from the engine compartment of the car.

Any help you can offer is appreciated. Any questions I can answer to start pin-pointing the issue, I am glad to (try to) answer.

Thanks,
Paul

I spoke with the service dept. and they suspect a collapsing radiator hose. I will have them confirm when it goes in for the timing belt change.

Walked out this morning and heard a faint whistle in the garage to find out it was the Sonata again...a full 10hrs after being driven the night before! I squeezed the radiator hoses and they felt fine and didn't change the sound. It definitely sounds as if it's coming from the passenger side of the engine bay...where you can see the AC tubing.
Any thoughts?
Thanks!

Dear Paul,

Just noticed that you had not been answered.

Since the location of the noise is not readily apparent, next time it starts the high pitched whistle get a long bladed screwdriver, start by touching the blade tip gently to the A/C tubing, put your ear to the handle, and see if the noise is loudest from that location. Try touching other areas and listening. touch the blade to the compressor and listen. touch the top of the radiator and listen. touch the valve cover and listen. Especially try to listen next to the high pressure and low pressure A/C couplings.

Once you have located the source, it could be a leaking A/C coupling, a pin hole in your A/C line, or something in your cooling system.

Byron

Byron,
Thanks for the reply.
I will do as you suggested.
It goes in tomorrow to have the timing belt replaced and the SD will also take a look.
Thanks,
Paul

SOURCE FOUND! What is it?!?

We had to cancel our appointment so the car didn't go in. However, it gave me some time to look at it some more. Yesterday I found the source, but the HMA service site is lagging so maybe someone here can tell me what it is.

It's actually an electrical component. It's in the engine bay attached to the passenger side fender wall very close to the power steering fluid and windshield washer fillers. It's black, about 2.5" in diameter and about 3" tall. It has an electical connector on the bottom (at least).

I thought it could be something electrical because at times it would change pitch...sounding like R2D2 was under the hood! :P When it was doing it yesterday, I pinpointed the area and gave the item a tap and the sound changed and then stopped. I'm guessing it's failing and/or overheating on hotter days.

Any help?
Thanks,
Paul

This post has been edited by paulbro: Jul 16 2008, 08:07 AM

Here's the component that changes/stops the noise when I mess with its wire harness. Anyone know what it is? It's location is posted in the thread above.
Thanks,
Paul