Steamy Windows!

Hello all,

A weird problem, this one - any idea why, when I turn my heater on to full
blast (no 4) and full heat on my 1996 Astra, do all my windows in the car
instantly steam up horribly, rendering it impossible to drive? It seems to
clear after about 5-10 minutes and the demisting effect actually starts to
do what it should! It's fine when the temperature control is on cold, but
I'm not driving like that in this weather!

BTW the heather blower only works on number 4 setting - I guess the
resistor's gone under the pollen filter (which I changed last week in the
vain hope of curing this steam-up problem).

 

Two possibilites spring to mind, knackered / leaky pollen filter ( I
think it's behind the glovebox on Astras) or leaking heater matrix. Is
there a faint smell of antifreeze that accompanies the steaming up? If
so I reckon it's the heater matrix.

 

There's obviously water getting into the heater system. Does it smell of
coolant, if so suspect a heater matrix leak. Otherwise check to see the
drain tube under the heater (which drops rain water out) isn't blocked.
And an thought, my 2002 astra often seems a bit damp on heater start if
It's been in the wet, so it may be a design deficiency in part

 

Drain tube under the heater? Under the inlet?

 

It's under the bonnet as is the air-con drain. Can be a bit difficult to
reach

 

as the others have said could be drain pipe or heater matrix.

get some clean tissue and once the car has nicely steamed up, clean all the
windows with it till its nice and wet, then smell it.
that will def tell you if it's heater matrix.

the other thing worth remembering is your recent change of the pollen
filter.

as it was only last week, the moisture will now be in the seats and carpets
and is very diff to shift this time of year

mike

 

Hi all.

Thanks for that - no, it doesn't smell of coolant. I reckon that blocked
drain tube is the thing - it's always worse after heavy rain, so that makes
sense. (That used to happen on all of the old BMC1100s I used to suffer.)

Thanks again!

 

If your pollen filter is sodden it will give these symptoms - here are
location instructions
http://www.puravent.co.uk/filters/dispfilter.pl?id=86

 

In message dpsoj.30895$,

I'm sure that the answers you've already been given are more likely to be
correct, but just thought I'd mention I my wife had a similar problem(in a
Nissan Micra) if the 're-circulate' switch was on. If the selector was set
to bring in fresh air from outside rather than re-cycling it, the misting up
problem went away...

 

Don't know if you still have this problem, but if you do it's probably a
leaking heater core.
If so, it's a messy job and usually the dash has to come apart.