Takes an age for the windows to demist

[raferackstraw]

a thing to check is the vynil around the screen vents hasnt peeled back and blocked the vents, had this on a mk1. do you have plastic inserts around the screen vents on a mk2

[The Mighty Elvi]

Warm air condensing against the cold window turns into water. As said open windows and full blast with the blower on windows.  Easier said than done on a MK2.  Tell tale sign of flap failure is bits of foam flying out of the air vents.  A sure sign. Also not getting a strong jet of air on 3.  You need to take out the airbox an reline the door flaps with neoprene or similar so that they are air tight.  Selector problems can be caused by snaped wires or in my case rhe small cog falling of the selector lever.  This fiddly b!tch is found behind the lower centre console. The selector slider arms move cables which are attached to an arm at the bottom. This arm in turn rotates The gear cog which moves the direction flaps.  Sometimes the cog slips through wear or drops off. 

[Ben Lessani]

I had a pinhole leak in the heater matrix, not enough to cause any kind of noticeable loss in coolant - but enough to build up a constant 1-2cm depth of water in the heater matrix housing. So whenever the heater was on, it was humid air, making it very difficult to demist the screen.

After replacement, even during winter, it took maybe 3 mins to defrost the inside of the glass.

Unfortunately, the only way to tell if this is happening is by opening and looking in the matrix housing.

[cняis]

I had a pinhole leak in the heater matrix, not enough to cause any kind of noticeable loss in coolant - but enough to build up a constant 1-2cm depth of water in the heater matrix housing. So whenever the heater was on, it was humid air, making it very difficult to demist the screen.

After replacement, even during winter, it took maybe 3 mins to defrost the inside of the glass.

Unfortunately, the only way to tell if this is happening is by opening and looking in the matrix housing.

K-SEAL is your friend.

Mine has stopped misting up now

[Diamond Hell]

Check for any dampness in the cabin and then look at the condition of the matrix, as Ben has said.

Alternatively go drive a Maestro for a couple of weeks and then get back in your Golf - everything should seem to be fine at this point.