Demisters
 

It appears air flow towards the windscreen on my newly acquired V40 is quite poor. Blows out of other vents alright when on the appropriate settings, noticeable drop in air flow to the cabin as you'd expect but not much at all coming out the screen vents. Pulled the cabin filter and it looks fairly new.

On top of this there is an irritating but low volume squealing noise coming through the system somewhere, only seems to happen either when on about 3 or 4, or when on slightly lower but travelling at a higher speed (more air coming in to the car from outside)... goes away by the time it's on full power.

Any tips for either of these please?

Following this one, as my windscreen demist is pretty lacklustre as well.

Most likely the seal between the heater box and the demister ducting. There is a foam seal between the joint that degrades over time and will let the air flow out under the dash instead of up the ducting. It is a dash out job to reseal. The heater box stays in the car and the demister ducting is attached to the underside of the dash.

Might put up with it for a while!

After starting the car 20 minutes before I left for work this morning because the windscreen was frozen, after that 20 minutes it had only defrosted barely the bottom half of the screen, so I intend to look into this soon, as by my logic if I can physically reach the affected joint then I should feasibly be able to whack some sort of sealant in whatever I can get to, even if it only improves things slightly then it'll help, I'm definitely not taking the whole dash out, that's just bonkers lol.

When I had a V40, I do recall the demister as being the most profoundly useless demister on any car I'd ever owned by a very long margin.

I checked everything I could and followed all the advice on the forum concerning probable causes. I never found anything wrong and nothing I tried made the slightest improvement.

I hope you have more luck than I had in getting it sorted

Martin

I have had two V40's and covered 400,000mls in them, never had a problem with the demister.

There is one joint between the heater box and the demister duct sealed by a foam seal - there are no other joints. This can only be accessed by removing the dash - a 1.5 hour job. The only other reason for a poor demister is the demister flap not working - again this can be accessed once the dash is removed.