|
|
|
#1
|
||||
|
||||
Intermittent heat in '91 350SD
My heat is acting up and I would appreciate some help/advice - I noticed this morning that it wasn't warming up even though the coolant was coming up to temp. The fan runs, but the air coming from the vents is not warm. If I turn off the ACC for a moment then turn it back on, the heat works temporarily - but only for a few minutes, then the air from the vents goes back cold.
It seems like the heat is working, just not making it into the passenger compartment. Any thoughts? Thanks!
__________________
Autos: 1991 350SD 276,000 miles 2001 VW Beetle TDI 115,000 miles Horns: 1955 Selmer Mark VI Alto (55,xxx) 1958 Selmer Mark VI Tenor (85,xxx) 1964 Selmer Mark VI Tenor (125,xxx) 1967 King Super-20 Tenor (430,xxx) 2002 Selmer Series III Soprano For Jazz Saxophone enthusiasts - check out my website... www.RustyBlevins.com |
#2
|
|||
|
|||
Sounds like the infamous monovalve failure to me. Normally a failed diaphragm that won't let it stay open.
|
#3
|
||||
|
||||
What is the remedy to this infamous monovalve failure? How can I determine if it is the monovalve or a failing diaphragm?
__________________
Autos: 1991 350SD 276,000 miles 2001 VW Beetle TDI 115,000 miles Horns: 1955 Selmer Mark VI Alto (55,xxx) 1958 Selmer Mark VI Tenor (85,xxx) 1964 Selmer Mark VI Tenor (125,xxx) 1967 King Super-20 Tenor (430,xxx) 2002 Selmer Series III Soprano For Jazz Saxophone enthusiasts - check out my website... www.RustyBlevins.com |
#4
|
|||
|
|||
Quote:
http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ42911DM6VZ&year=1991&make=MB&model=350-SD-001&category=All&part=Mono+Valve+Repair+Kit The usual solution is to buy this rebuild kit and install it (4 screws on the top of the monovalve to replace the internals). If you take out the internals, you should be able to see if the diaphragm is damaged. |
#5
|
|||
|
|||
It's likely you can get full heat by unplugging the monovalve until you get it fixed.
__________________
1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#6
|
||||
|
||||
Is there a monovalve replacement/repair instructions thread? Is it an easy DIY?
__________________
Autos: 1991 350SD 276,000 miles 2001 VW Beetle TDI 115,000 miles Horns: 1955 Selmer Mark VI Alto (55,xxx) 1958 Selmer Mark VI Tenor (85,xxx) 1964 Selmer Mark VI Tenor (125,xxx) 1967 King Super-20 Tenor (430,xxx) 2002 Selmer Series III Soprano For Jazz Saxophone enthusiasts - check out my website... www.RustyBlevins.com |
#7
|
||||
|
||||
Quote:
Edit: Here is the link, my pictorial begins at post #42 http://www.peachparts.com/shopforum/showthread.php?t=206723&page=3
__________________
-diesel is not just a fuel, its a way of life- '15 GLK250 Bluetec 118k - mine - (OC-123,800) '17 Metris(VITO!) - 37k - wifes (OC-41k) '09 Sprinter 3500 Winnebago View - 62k (OC - 67k) '13 ML350 Bluetec - 95k - dad's (OC-98k) '01 SL500 - 103k(km) - dad's (OC-110,000km) '16 E400 4matic Sedan - 148k - Brothers (OC-155k) |
#8
|
||||
|
||||
Wow, thanks!
Okay, now that I know where the monovalve is and how to take it out, how do I go about determining whether it is the culprit of my heat problem? From the car's symptoms and what I have read here, I don't think it is the core b/c I do have good, hot air from the vents - just not all the time. Anything else I should consider/check to get closer to isolating the problem?
__________________
Autos: 1991 350SD 276,000 miles 2001 VW Beetle TDI 115,000 miles Horns: 1955 Selmer Mark VI Alto (55,xxx) 1958 Selmer Mark VI Tenor (85,xxx) 1964 Selmer Mark VI Tenor (125,xxx) 1967 King Super-20 Tenor (430,xxx) 2002 Selmer Series III Soprano For Jazz Saxophone enthusiasts - check out my website... www.RustyBlevins.com |
#9
|
||||
|
||||
Look at the pics I took. I showed a pic of a torn diaphram. If that little rubber piece that moves is torn (you should easily be able to tell with it out) then thats your problem. Only way to tell is to remove it.
__________________
-diesel is not just a fuel, its a way of life- '15 GLK250 Bluetec 118k - mine - (OC-123,800) '17 Metris(VITO!) - 37k - wifes (OC-41k) '09 Sprinter 3500 Winnebago View - 62k (OC - 67k) '13 ML350 Bluetec - 95k - dad's (OC-98k) '01 SL500 - 103k(km) - dad's (OC-110,000km) '16 E400 4matic Sedan - 148k - Brothers (OC-155k) |
#10
|
|||
|
|||
I had the same symptoms as you did. Per guidance from this site, I installed a Mono Valve Repair Kit. The diphgram was not torn in the old valve, but the heat has never worked as well as it does now.
|
Bookmarks |
|
|