Hi guys,

Please help advise... in my 87 951, whenever I tune up or down the temperature dial of my climate control on the dash, there will be some coo... coo... coo... coo... coo... sound from behind the climate control panel inside the dash.

The coo... coo... coo... sound will continue for a few seconds, and then stop. It sounds like a bird is hiding behind my dash making those sound. Or, it also sounds like some kind of dry gears trying to turn, and badly needs some lube.

Despite this strange sound, everything seems working fine. The climate control keeps the temperature cool/warm, and the A/C is cold.

Should I worry that something expensive is going to break soon?

Thanks much, and with best regards,

- Alex.

 

Maybe a vacuum leak while the system is purging? Is it definetly inside the cabin? check the firewall vacuum lines with the hood up to isolate the location of the noise.

 

I think I am pretty sure that the sound is inside the cabin... I can almost feel it right behind the climate control dials when I put my ears close to the dash...

I also just replaced all old vacuum lines, to new ones, under the intake manifold. The vacuum line job was done by an experienced P-car shop, and they have checked no leaks on the new vacuum lines that they installed.

The coo coo sound did happen before and after the vacuum line job, though. Would there be any other vacuum lines (climate control related) that is not under the intake manifold, and would relate to this coo coo sound?

Also, are there any moving parts behind the dash, which will be moving or operating, while I turn the climate control dial? Just curious because the coo... coo... sound was also like dry gears moving...

Many thanks, with best regards,

- Alex.