[W126 Coupe] Is this a monovalve problem?

[Tom Oelsner]

Hi Dick
See Below


  -----Original Message-----
  From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com]On Behalf Of Dick Spellman
  Sent: Thursday, December 07, 2006 4:13 PM
  To: Mercedes Coupes Mailing Lists
  Subject: Re: [W126 Coupe] Is this a monovalve problem?


  Hey Tom:

  Could be mono-valve then again maybe not.  If you throw the temp dial
until it clicks in the red, do you get hot air?   Not until I am standing
still.   If you then throw it to click in blue do you get cold air?   Yes
If you then throw it in the red but, not all the way to the click do you get
hot air?  Not if f I am driving.

  Another way to test the mono-valve(s) directly is to apply 12vdc to the 2
pin terminal atop the valve and see if you get hot air.   What current?
Other possibilities are ignition switch, or climate control head or possibly
a sticking fresh air make up door which would be the two vacuum element flap
up under the passenger dash.

  Anyway, you need to test further and report your findings.  If you are
inclined, just pull the mono-valve head and see if it's 1. fouled with
sludge and 2. showing signs of a ruptured rubber seal.  If sludge only clean
and re-install, if ruptured, replace. ($20-40 depending on where you buy MB
stuff)  I figure I'll do it when I am taking time off from work at the end
of the month.

  Regards,

  Dick
  btw:  took a position this past summer in the Northeast for a company with
US hq's in Sunnyvale (home of fantastic sushi) and world hq's in Kobi and
Kyoto, Japan (home of world's best steak, would you believe?)  Same field as
before just doing more work for the US govt as a result.  Having fun too.
Let me know how the new job is going.

  .toelsner at comcast.net wrote:
    Happy Holidaze to Everbody,
    Well it is finally getting cold enough to turn on the heater in the
mornings...now here is the scenario.
    When the car warmed up enough to turn on the heater, it was only blowing
mildly cool air no matter what the temp setting or what buttons were
pressed.  Driving speed was 75-85 (hey this is CA).  As soon as I stopped at
a light, the air blew HOT.  The next day I tried a variation...drove the car
until warm, pulled over and waited to see if it blew hot air.  Air only
remained mildly cool.  As soon as I started driving, it blew hot.  I turned
down the temp until it blew cold and then turned up the temp...only got
mildly warm.  At the same stop light as the previous day, it blew hot.
560SEC has around 165k miles on it.  Does this sound like a monovalve
problem?

    btw..saw a great license plate on a new MBZ when in LA earlier this
week...hys2pid..maybe it was hys2upid...I was dodging traffic when I saw it

    Tom Oelsner
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