condensation

[laraa at sympatico.ca]

IF the AC system is similar to the one in the 200, that recirc flap default
position is recirculation (via a strong spring). Then, when engine is
running and provides enough vacuum, a vacuum motor will force against the
spring to allow fresh air (unless recirculation is selected at the AC
panel). I've seen a few with a broken tab for the vacuum motor linkage,
hence the permanent recirculation mode. That spring is really stiff, BTW.
And since the flap vacuum motor is not an electric stepper motor, then the
system can't detect a fault there.

There is an easy test to do : activate the AC system with engine running,
fan in high speed and toggle the recirculation function. You should hear
clearly a change in noise level in the cabin after 2 or 3 seconds. You can
also open the hood, and place a dish towel or an appropriate-sized sheet of
paper over the intake grille for the AC at the base of the windshield. With
a good recirc flap, air flow will suck the towel/paper sheet to the grille
or not when you toggle it. If you can't feel it sucked to the grille, then
the flap is stuck in recirc mode. It's somewhat obvious.

Beware that some systems won't allow recirculation if it is in defrost or
partial defrost mode; you may have to force vent or floor heat.

Louis-Alain



-----Message d'origine-----

No, I'm not sure of that.  A much easier job always appeals.  ;-)  I 
assume that the HVAC diagnostics could tell for me.  Guess I need to 
break out Mr. Bentley.


Bob



At 08:18 AM 12/1/2011, laraa at sympatico.ca wrote:
>Bob, are you sure it's not the recirculation flap that is stuck closed ?
>Same symptoms, a much easier job to do...
>
>Louis-Alain
>
>
>
>-----Message d'origine-----
>
>Hi Y'all,
>
>My urS6 has shown condensation on the insides of the windows on a
>couple of recent chilly mornings.  I figure it's about time to
>replace the heater core.
>
>1.      Is there another likely diagnosis for the condition?
>2.      Is there a write-up on heater core replacement somewhere?
>3.      Source of parts?
>4.      Any tips?
>5.      How big of a job is it?
>
>Bob
>
>
>
>
>-----
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