HVAC whistles like a boiling kettle.
 

Hi all. Anyone had this? It’s louder with speed of car. Oddly silences when switched to recirculate air.

:Confused:

If its still got the same air con compressor as the D2 then it could be the electro-magnetic clutch on it singing when the air con is on, if i turn mine to eco then the noise stops. Getting the compressor swapped soon on it

Cheers for that. Any idea why it would silence on recirculation? I can see why it would on ECO.

maybe on recirc the aircon function is cut as its just wanting to recirculate what air is in the car, but its just a guess.

Yeah. I don’t think it does cut the A/C. Hope your compressor swap isn’t too painful.

Might be a jammed flap, creating a restriction.

Have you tried opening/closing different vents to see if it changes (or to see if you can get a tune :D) ?

If you find the note of the whistle is affected more by certain vents it might provide a clue as to what/where the restriction is.

I am pretty sure D3 will have permanently driven compressor without a clutch.

A/C compressor is permanently driven with variable output (no clutch).
I would focus investigation under the pollen filter.
Open the bonnet
Remove rubber seal (weather strip)
Remove left and right plastic cowels (where the brake fluid reservoir peeps through.
Use a large flatblade screwdriver to press and undo 4 plastic retaining screws 90degrees.
Lift pollen filter housing and filter together towards you and upwards while holding filter in housing underneath with your fingers.
Look into void covered by filter.
Operate recirculate and observe flap actions and noises.

When reassembling, ensure that the 2 spikes on the windscreen cowel insert into the rubber gutter spouts on filter housing.

Another thing is air is entering the car and has to leave somewhere, normal place is vents behind the trim in the boot but could be a gap in windows or doors, check windows are shut and sealed. In recirc mode, the air is no longer leaving the car so no whistle in any holes or gaps.

I had something like this in a car many years ago.
Resolved to a dried leaf.
Hope that it is a cheap fix.

Thanks for all the replies. I replaced the blower motor a year or so ago, so know all about that fiddly business.

The noise is the same whatever way the air is directed.

It does sound like its coming from behind. And was after I’d changed two door handles and a lock actuator. Can’t see how related, as no gaps in window closure, door cards back on well etc. But maybe I’ve missed something Snap’. Thanks for the input. Will have to revisit when not dark and/or raining.

Where was said leaf Ray?