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  #1  
Old 11-04-2001, 12:36 PM
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more monovalve questions

I couldnt find much info in the archives on monovalves for later 93 W140 S-class (400SEL)
.
Im wondering how I can isolate this as the problem.
I have no heat.
I read something about a guy pinching the heater hoses off, but I tried that and still got no heat. Is that how you determine its the monovalve? there are 3 hoses going into one half and one into the other part, it looks like a two stage monovalve.
I wasnt sure how long to keep it pinched off before heat would come out.
I guess i dont want to buy a $453 dollar part if im not sure it will fix my problem. Could it be a door or flap is not opening? is there a way to isolate the valve as the problem? I pinched all 4 hoses and still had no heat, but only for a few seconds each.
How does the climate control buttons open the doors and flaps with microservos? I hate this, winter is coming soon here, and I cant afford $1000 to just fix my heater. Is there a cheap jerry rig fix? I dont care anymore.
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  #2  
Old 11-04-2001, 04:13 PM
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Location: Evansville WI
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HI:
The thing to remember about these watervalves is that "0" voltage=full heat. This is a failsafe incase of a climate control electrical failure. They plan on the worst scenario and try to make the situation as safe as possible. By looking at it this way, they figure full heat will keep the windshield clear on a cold damp day. If this happens in the summer time, I guess they figure you can roll down the windows and open the sunroof.
At any rate, if you operate the car with the electrical connector disconnected, you should have your full heat. If it does go to full heat, it means the system has failed in such a way that there is constant 12 volts going to the water valve, maybe a bad interior temp sensor, that would be my first guess, second guess would be the control unit (control panel) itself. I wouldn't replace anything before getting a proper diagnosis done.
Gilly
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  #3  
Old 11-10-2001, 10:29 PM
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Posts: 46
even MORE monovalve questions!

Ok, Totally disconnected the electric connectors from the monovalve, and still no heat. Replace the monovalve?
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  #4  
Old 11-11-2001, 12:50 AM
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Well, I hate to tell anyone to go ahead without a good diagnosis unless I'm really 100% sure, at least 90% sure. i'm only about 75% sure in this case. the aux pump is possibly bad, but you should still have adequate heat without that working. The power and ground shouldn't have any effect due to the failsafe mode i mentioned before. Low coolant I'm sure you would have noticed, that of course is a possibility on all cars with a heater using the engine coolant (liquid) for heat. Maybe a flap problem in the heater case, but not really common. The heater core will usually way overpower the evaporator section of the A/C, so I don't think it's a failure of that nature.
One thing bothers me, and that's that this isn't a real mono-valve, it's a duovalve, that's why you have driver and passenger settings for the heat. It seems liekit would have to be a dual failure of the valve, both sides went bad, unless there is something that can fail that would affect both sides, but I don't think there is. Another problem I see is that these hardly ever fail. I know I have replaced them before, been so long I can't remember what for.
As a final test, get the engine warmed up and run the defroster, then check to see if the hoses that run to the interior are getting hot or warm at all. The engine side hose should get a little warm, even without good flow through the valves. You could also take the hose off coming from the engine to check for some (?) kind of obstruction, also check the return hoses for any kind of kink in it which may obstruct flow.
Gilly
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  #5  
Old 05-28-2003, 09:55 PM
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Join Date: Dec 2000
Location: Mountain Island Lake, Charlotte NC
Posts: 376
e420 duovalve part number

Can anyone tell me the part # on the 97 E420 Duo Valve(duovalve)?
Thanks!
__________________
Rob Armstrong, Charlotte, NC
Mountain Island Lake
RobAinCLTNC@hotmail.com

2004 VW Passat GLS TDI-50k
2006 Honda Odyssey EX-L 7k
FOR SALE 1991 300TE 228k

2003 Subaru Outback 57k Silver/Black-SOLD
2005 C230K 18k Pewter/Grey-SOLD
1997 E420 108k Black/Grey-SOLD
1986 560sl 200k Black/Palimino-SOLD
1985 300sd 340k-SOLD
1979 240d 170k-SOLD
2000 Volvo V70XC-POS couldn't sell fast enough
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  #6  
Old 05-28-2003, 10:29 PM
Registered User
 
Join Date: Dec 2000
Location: Mountain Island Lake, Charlotte NC
Posts: 376
e420 duovalve part #

Can anyone tell me the part # on the 97 E420 Duo Valve(duovalve)?
Thanks!
__________________
Rob Armstrong, Charlotte, NC
Mountain Island Lake
RobAinCLTNC@hotmail.com

2004 VW Passat GLS TDI-50k
2006 Honda Odyssey EX-L 7k
FOR SALE 1991 300TE 228k

2003 Subaru Outback 57k Silver/Black-SOLD
2005 C230K 18k Pewter/Grey-SOLD
1997 E420 108k Black/Grey-SOLD
1986 560sl 200k Black/Palimino-SOLD
1985 300sd 340k-SOLD
1979 240d 170k-SOLD
2000 Volvo V70XC-POS couldn't sell fast enough
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