just replaced the inserts on the Monovalve (Euro version, have two inserts!).For the second time in the last three years I might add...
Before wrapping everything up, I noticed there is some coolant wetness on the outside of the valve, at the bottom . Before I tear the valve itself out just to be able to see for myself, I was wondering whether anyone has knowledge about this ? I could not find any info in the CD as to whether there Is there a seal down under that can be replaced, or would this mean I need to get a new valve?
TIA

The plastic housing can crack. check it carefully.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

as mentioned plastic can crack, also check hose connections, check tightness of screws that hold on the cover, make sure the auxillary water pump is not cracked or leaking

__________________
Ron
2015 Porsche Cayman - Elizabeth
2011 Porsche Cayman - Bond,James Bond
Sadly MERCEDESLESS - ALways LOOKING !
99 E320 THE Queen Mary - SOLD
62 220b - Dolly - Finally my Finny! Sadly SOLD
72 450SL, Pearl-SOLD
16 F350 6.7 Diesel -THOR
19 BMW X5 - Heaven on Wheels
14 38HP John Deere 3038E Tractor -Mean Green
84 300SD, Benjamin -SOLD
71 220 - W115-Libby ( my first love) -SOLD
73 280 - W114 "Organspende" Rest in Peace
81 380 SL - Rest in Peace

I will try and clean all the residue (hard to reach) and see if the housing remains dry.
I am guessing it is not the hoses - they connect to the, (for lack of a better term)- "thinner" part of the valve well below the suspect area. That suspect area is right below the wide part of the monovalve (where the inserts reside).
I need to check further, but I do not think it is the aux water pump either -
The leak, if there is one is only from the passenger side of the valve. That would rule out the aux water pump, would it not ?
thank you all and I will keep you posted.

Be sure the 4 screws are good and snug. I was losing coolant for this reason.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

if you eliminated the other possiblities and the 4 scews are snug then you probably have a hairline crack. The screws go into plastic so they are easy to strip. If this is the case perhaps you can fill with epoxy and retap. The whole unit is pricey

__________________
Ron
2015 Porsche Cayman - Elizabeth
2011 Porsche Cayman - Bond,James Bond
Sadly MERCEDESLESS - ALways LOOKING !
99 E320 THE Queen Mary - SOLD
62 220b - Dolly - Finally my Finny! Sadly SOLD
72 450SL, Pearl-SOLD
16 F350 6.7 Diesel -THOR
19 BMW X5 - Heaven on Wheels
14 38HP John Deere 3038E Tractor -Mean Green
84 300SD, Benjamin -SOLD
71 220 - W115-Libby ( my first love) -SOLD
73 280 - W114 "Organspende" Rest in Peace
81 380 SL - Rest in Peace

gidpor -

If yours is toast and can't be epoxied, let me know. I bought the valve for my 280 euro but only used the inserts - I'll let the valve body go cheap if you need it. I paid $191 which means I have about $150 worth of valve body in a box in the garage.

By the way - "monovalve" ? maybe we should call it a duomonovalve...?

Kevin

How about Duovalve ?
Thank you kevin for your offer as well as the advice from meltedpanda,Mike Murrel and dmorrison.
I hope my eyes are not playing tricks on me, but after cleaning the (above mentioned - mono,duo,trio) Valve and driving around - it seems to be dry. Will stay on top of this for a little while. Perhaps I did get some coolant splashed about after all while putting the inserts in. Did not think so...

Kevin, this one is for you - Since my heating issue did not go away I will start a new thread regarding that. However while I searched through the MB CD with a comb - with no luck, I discovered it really is called a duo valve. How about that !