Dashboard chatter - Issue known by Volvo
 

After living with my V90 for a few months I became increasingly aware of an irritating noise from behind the dashboard.

You could describe it as a squeak, chirp or chatter. It sounded like a ventilation fan motor, and when I turned the fan off - the noise seemed to stop

The sound was intermittent, but seemed to announce itself always as the car moved off from a standing start, and sometimes in motion.

I asked the dealer to investigate, under warranty.

The master tech found a Technical Update on their database, that cites the issue manifesting as a sound like "birdsong" (the "chirping")

The issue is apparently well known to Volvo. It's a short coolant return hose going back to the expansion tank. The short hose arrangement results in air being drawn into the coolant, and the resulting air bubbles cause the chirping sound. A bit like a venturi syphon effect

The Volvo solution is to have a modified (longer) return hose fitted. This goes deeper into the liquid in the expansion tank and so reduces the likelihood of air being drawn in.

The master tech told me he had to run the car for 1.5 hours at 2000 revs to fully bleed the cooling system

So far it appears to have done the trick

So if anyone else experiences a funny chirping / chatter from the general dash area, it's worthwhile asking your dealer to search their database for the Technical update under "birdsong" and get this annoying shortfall in the original design corrected whilst your vehicle is still under warranty

I imagine it applies to all the SPA vehicles