Anyone fix their mono valve using a mono valve repair kit? If so, do you
drain coolant, take 4 screws out, remove cover, then valve?
Didn't see any threads here that explained the repair.
Thanks.


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1984 MB 300 SD Turbo

I'm waiting for my repair kit to arrive from Phil so I can fix up my CD.

From the reading I've done, you just take out the screws and replace the innards. You might lose a few drops of coolant, but no need to drain anything.

EDIT: I think even if you were replacing the monovalve and not repairing it, you could avoid draining the coolant by just using some clamps on the hoses to pinch them off while working.

__________________
Chad
2013 Jeep Unlimited Rubicon
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL

no need to drain coolant- you will not loose much, if any.

__________________
1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

Might take as much as 10 minutes including drinking a beer while you do it. 5 minutes if no beer.

No coolant loss, don't drain.

Some of the repair kits on ebay are defective but the rubber parts are good. Save you old one and combine it with the rubber off the cheap one so you'll have a good spare.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

Yep, no coolant loss. Just be careful with the wires as they are old and brittle.

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad

There are monovalves sold in the parts section....
quite cheap....

There are some repair kits that "replace" the entire unit, not just a new mono valve itself.
I have only swapped out the valve, as mentioned, five minutes, four screws no coolant loss.

__________________
83 SD

84 CD

Those are mega bucks that replace the entire unit. I'd say it's closer to three minutes....

I'd agree with 3 minutes. I don't remember any coolant loss at all. Disconnect the electric (I did, anyway), take out the 4 screws, pull the bad guts out, put the new one in, reconnect elec., drive forth in warmth. I think I even took it off the firewall, and it was still under 5 minutes. Wish all repairs were that easy. I got my replacement at *************** for about $35. If I could figure out how to replace the rubber diaphragm that's bad in my old one, I'd fix it for a back up, but so far I haven't figured out where to get them. Don't know if it's possible to do yourself or not, but I still have my old one, just in case. Why not take some pics and put it on the DIY page when you replace it? Wish I would have. Like rocky racoon said, you could snap a picture and drink a beer between each step. (All 3 of them)

__________________
"Knowing is not enough, we must apply.
Willing is not enough, we must do." Goethe

***********************************


1951 Chevy 3100

2003 Indian Chief Roadmaster

1983 GMC 1 ton Dually

1982 Chevy 1 ton Dually, service body (sold)

'90 GMC Suburban 6.2 "SS Veg-Burban"
(single tank WVO\diesel conversion) SOLD

'81 300D ~ Mama's car...my job (now my car)(but still my job) SOLD

'83 300sd ~ rescue car SOLD

2005 Ford Taurus (Mama's new car)(NOT my job!)

Thanks guys. I did order one from ********AZ, comes next week.
Seems too easy to take pics. ( Probably just jinxed myself )


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1984 MB 300 SD Turbo

Yes its very easy, just take it out and put it back in the same way.

__________________
-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)

coolant just barely trickles out. not enough to make any kind of difference. it is the most simple repair. the only hard part for me was i have the 85 300SD where all of the electronics are stuffed behind a secondary firewall.

__________________

• 1993 Mercedes-Benz 400E *146,000 Miles*
• 1985 Mercedes-Benz 300SD Turbo Diesel Biodiesel *SOLD @ 346,000 Miles*
• 1984 Mercedes-Benz 300D Turbo Diesel Biodiesel *SOLD @ 284,000 Miles*

I agree with all above....its a 10 minute no brainer, but just a word of caution...

To be honest, I don't remember the details since its been a few years since I have done this, but I seem to remember in some of the older posts here from very knowledgeable individuals that you want to avoid frying the climate control ECU (elect. control unit) when working on the monovalve. As I said, I don't remember the details (is the wire hot when the car is off? how can you actually fry the ECU? or maybe its the pushbutton unit that can be fried? etc.). Regardless of the details, be very careful with the electric leads to the monovalve. As with most work on cars, its a good practice to disconnect the battery as a routine safety measure (most of us don't do this, but we should). The electric leads are brittle, and you just don't want to run the risk of shorting something here and having to replace an expensive and hard to find ECU or pushbutton unit.

Mark

__________________
1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

I have a slow screwdriver!

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83 SD

84 CD