My 420 SEL recently had no heat, so I replaced the monovalve. Now I have heat in the front (and defrost), but no heat for the rear passenger compartment. Anyone?

Jim,

One thing to keep in mind is that heat in the rear on these cars comes through ducts under the front seats, NOT through the vent at the back of the center console (that's for fresh air only).

I'm not sure where it is, but the problem you're having is probably related to the dampers that control air flow into these ducts. I believe this is under the dash/part of the main center console. However you probably should check to make sure that there isn't anything, such as carpeting, blocking the vents where they exit under each front seat. You can see them if you move the front seats all the way up and forward.

jlc

__________________
Jeff

'87 560SEL 267K (177K on motor) Blue/Blue
'98 Buick LeSebre 60K (wife's car)
'56 Imperial Sedan 124K
Past Cars:
'67 Dodge Monaco 130K (Sold)
'87 Chrysler 5th Ave 245K and going strong (sold)
'73 Plymouth Satillite 175K (sold)
'96 Chrysler LHS 80K (totaled)

If I'm following what you're posting, I don't have anything wrong. I have beaucoup heat from the floor vents, just cold air from the rear center vent. Good to know. Thanks.

Jim,

You're welcome. This is a common question this time of year for folks new to life with a W126 - I asked it two years ago as well. Just close the lever on the center vent to cut off the cold air in back (unless, of course, it's your mother-in-law who sits in back )

jlc

__________________
Jeff

'87 560SEL 267K (177K on motor) Blue/Blue
'98 Buick LeSebre 60K (wife's car)
'56 Imperial Sedan 124K
Past Cars:
'67 Dodge Monaco 130K (Sold)
'87 Chrysler 5th Ave 245K and going strong (sold)
'73 Plymouth Satillite 175K (sold)
'96 Chrysler LHS 80K (totaled)

New, I am. I just got this at the end of October.

That's what I did thinking it was just an interim fix.

Actually, she gave me the car. I have to stay on her good side!!!

"quote:
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unless, of course, it's your mother-in-law who sits in back
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Actually, she gave me the car. I have to stay on her good side!!!"

Does your wife have a sister? Does your mother-in-law have another 420??

__________________
Earl McLain
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)