Info/advice needed: heater core...

["Gerard van Vaugh" <gerard@acenet.co.za>]

Hi!

I am slowly repairing things on my 1990 200.
A month or 2 ago I was experiencing heavy
misting on my windows in the rain or cold
when I used the heater vents to defog. Also,
after using the vents and leaving the car
for a while in the sun with either sunshades
up in the front or sometimes without them
I can return to the car only to find that most
of the front windscreen is coated in water
(not fine misting, but larger areas covered in
large drops). The instrument cluster also
now has water marks showing the condensation.
I was informed by listers that this has
something to do with a leaking heater core.
Faint musky or "garage" smell, but I'm putting
that down to the smell of anti-freeze. Oh yes,
eventually windows become coated in grimy
substance.

As a helpful tip I've discovered that first
switching the aircon unit to LO and then
switching it off before shutting down the
car does help prevent the build up of
moisture.

Anyway, I was also told that identifying
and repairing the leaking unit is quite a
mission. So, would it be possible to get
some details on how to repair/replace this
heater core? I'm basically looking for a
detailed description of what to do to
identify if is a leaking core and how to
repair or replace whatever parts. This can
act as a reference for whoever is willing
to store the stuff one of those websites
I hear listers are going to start building
for specific models.

Anyone BTDT with leaking heater cores or
massive humidity buildup within these
type-44 cars?

G.