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#46
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Quote:
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#47
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Here is what I got for $95
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1995 E300 diesel |
#48
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Looks like the early style without integrated recirc pump. Is that what's on your car now?
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#49
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I didn't look closely enough to see if the pump was part of the same piece on my car but it is.... hope this doesnt mean a $500 part.... I'll just clamp off the coolant hose if that is the case
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1995 E300 diesel |
#50
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but the brass point is not connected, it just fits in the sleeve so how does the solenoid retracting pull it up?
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1995 E300 diesel |
#51
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Hope you don't have problems returning that wrong monovalve. Jeremy
__________________
"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#52
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Quote:
I don't anticipate any problems returning the part.
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1995 E300 diesel |
#53
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Monovalve
Quote:
If power to the monovalve fails, the default position allows hot coolant to flow through the heater core, so that you always have heat to melt an iced-up windshield in the winter. That is a safety decision on the part of Mercedes. Obviously, such a failure in the summer is not very much fun. It is also possible that someone before you put the hoses on the monovalve incorrectly. The two spigots at the bottom go to the firewall where they connect to the heater core; the top spigot (in the section that tends to crack) goes to the bypass line from the head and the little spigot on top is capped off. The heater core has one hose in and two out because it is the same heater core used in models with manual climate control, which have dual-zone heat controls (these were not officially imported into the USA but we got the same heater core). Here is a crude drawing of the plumbing: Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 Last edited by Jeremy5848; 07-03-2013 at 04:52 PM. Reason: Add drawing |
#54
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The plumbing to the washer bottle is odd - the pump has to fight flow from the head. Why not heat the washer bottle from the head and return downstream of the pump?
Sixto 87 300D |
#55
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Here's how the 1995 E300D Monovalve Works
I took my spare monovalve apart and played with it, figured out how it works. Here's how, with pictures.
In "normal mode" the Automatic Climate Control (ACC) calls for heat. Power to the Monovalve is OFF. Hot coolant flows from the back of the head through the heater core (in 1 pipe, out 2 pipes) and through two rubber hoses to the lower twin inputs of the Monovalve. The "float valve" (brass pointy thing) is pushed up by the flow of coolant and the coolant flows through the valve, helped along by the auxiliary pump, and returns to the thermostat housing. If either the ACC or the monovalve coil fails (electrical failure) the float valve will still be pushed up and hot coolant will still flow through the heater core. This guarantees heat to clear a frozen windshield in winter. It also guarantees an uncomfortable car if this failure occurs in the summer, oh well! When the engine is off, car parked, the float valve sinks to the bottom, closes the valve, and prevents hot coolant from flowing backwards from the radiator into the heater core. In theory this should prevent the climate control system from blowing a lot of hot air when you re-start the engine and re-engage the air conditioning. In "bypass mode" the Automatic Climate Control (ACC) DOES NOT call for heat. Power to the Monovalve is ON. Hot coolant cannot flow through the heater core because the float valve is forcibly closed by the electric solenoid. However, this same solenoid action opens the bypass valve, allowing hot coolant to flow from the head, bypassing the heater. The coolant flows through the bypass valve, helped along by the auxiliary pump, and returns to the thermostat housing. Please note that this is a very simplistic explanation focusing on the way the Monovalve works. ACC actually pulses the Monovalve on and off to control HOW MUCH hot coolant is allowed through the heater core, thus regulating the temperature of the passenger compartment. This can occur even if the air conditioning is working; it's especially nice in humid climates to have the a/c freeze some of the humidity out of the air even if the heater is on a little bit. Except for a very few late-late-1993 (~May 1993? production) 300D-2.5 cars (W124.128, OM602 Turbo), this special monovalve (001 830 40 84) is unique to the OM606NA engine in the 1995 E300 Diesel (W124.131). My guess is that Mercedes did this so that there would always be a constant flow of coolant from the back of the head, thus keeping the head at a more constant temperature, thus improving smog control. I invite you to come up with a better guess. It is possible that one could simply block off and abandon the bypass line and use a "regular" (separate) monovalve and auxiliary pump, or even the simpler and less expensive combined monovalve/pump (001 830 39 84) used in the 1994-95 E320 gasser. If you choose to go that route, please let us know whether your engine burns up or not. Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#56
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I may have that arrow backwards.
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#57
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I put 12v to mine and although i got a little sparking- no thunk or other noise to indicate the valve moving. Maybe I'll try to find one at a used parts yard, there is one for foreign cars not far away.
When I put vice grips on the line going into the heater core (from the wiper fluid tank) I get no heat in the cab.
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1995 E300 diesel |
#58
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Diagnosis
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OTOH, an internal leak may continue to leak, making the repair only temporary. Regretfully, the seals cannot be purchased separately. Incidentally, the metal solenoid coil is common to some (but not all) monovalves. If you have a chance to pick up several in a junkyard they might come in handy (I paid $7 for the last one I bought a few months ago -- tell 'em it's a "heater valve."). A monovalve that has not leaked will last a long time even in a junkyard. The vice-grip trick confirms that the heat you are getting in the cabin is from coolant passing through the heater core when it should be off. That pretty much pins down the cause to the monovalve. Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#59
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I got the correct part today at a junkyard, $60 and they tested it before I bought it. Came from a gasser 124.
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1995 E300 diesel |
#60
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Brian Carlton's [in]famous response haunts me How can the correct replacement for a Diesel only part come off a gasser? What am I missing?
Sixto 87 300D |
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