Hello everyone, my Octavia is making a loud high-pitched whistling sound at idle coming from the engine bay. I've got a video of it uploaded to reddit Here.

 

The sound goes away when revved past 1200rpm so only noticeable at Ide or when the clutch is down. There's no leaks, no drop in performance or any other signs. just an annoying whistle. I've took it to one garage and the guy seemed to think it might be the A/C compressor on its way out. The A/C in the car isn't brilliant I must say its not blowing Icy cold like it should. Just curious if anyone has an idea what might be the cause or source of this whistle and what can be done to get it resolved? Many thanks in advance.

Difficult to say from the video.

 

Try pouring a cup of water on the auxiliary belt whilst the engine is running, it may just be a dirty/glazed/old belt.

8 minutes ago, MicMac said:

Difficult to say from the video.

 

Try pouring a cup of water on the auxiliary belt whilst the engine is running, it may just be a dirty/glazed/old belt.

I'll give it a go and report back!

14 minutes ago, MicMac said:

Difficult to say from the video.

 

Try pouring a cup of water on the auxiliary belt whilst the engine is running, it may just be a dirty/glazed/old belt.

No luck with this I'm afraid. 😞

With the engine running try squirting an aerosol can of brake cleaner around all intake hose connections, injectors etc.  You may have a leak somewhere and it will briefly stop when you target the source.

 

Unless you are intimately familiar with your engine, I would suggest you blanket spray one section at a time, avoiding a hot exhaust, rather than try to pin point immediately.

So for an update. I found there is a slight leak of coolant coming out of this particular part on the engine above what I assume is the turbo.  I have no idea what this part is and I'm unsure if it would be linked to the whistling sound I can hear? 

If you can get a 1m length of flexible hose e.g. garden/washing machine/fish tank etc.  put one end to an ear and sweep the other end around paying attention not to touch any moving parts.

 

You should then be able to localise and then pinpoint your problem .

Could be the water pump?

 

It's down at the bottom left of the engine.

 

Does it only make this noise when the engine is warm?

30 minutes ago, Phil-E said:

Could be the water pump?

 

It's down at the bottom left of the engine.

 

Does it only make this noise when the engine is warm?

Yeah only when it gets up to temperature does it make that whistling sound. I did get the leak fixed today however, an O ring between the coolant line and the turbo had perished so about £30 to replace that. Funnily enough the sound seems to have gone somewhat since getting that o-ring replaced.  

Did they replace any of the coolant by any chance?

 

I've heard that a certain coolant type causes the seal in the water pump to squeal.

Edited 9 August, 20223 yr by Phil-E

1 hour ago, Phil-E said:

Did they replace any of the coolant by any chance?

 

I've heard that a certain coolant type causes the seal in the water pump to squeal.

He mentioned he had topped it up after changing the O ring. Do you think it's still worth getting the water pump looked at?

Have a visual check of it if you can. It's driven off the auxiliary belt so it's visible (not like they used to be when driven off cambelt etc).

 

If there are no signs of leaks then it should be fine. It could mean the seal wears out and it starts to leak.

 

Mine did it last since I owned it for 2 years. But then last year the coolant had dropped slightly so I topped it up and since then the noise has gone. And no signs of any coolant leaks.