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  #1  
Old 02-09-2003, 04:24 AM
EricSilver's Avatar
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Location: Fairfax, VA
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Exclamation Hot Coolant in Washer Fluid Reservoir

Car: 1989 260E
178,000 miles

Today, after a fairly short highway drive, my car began to run hot -- a steady 105 degrees or so -- as a result of sudden coolant loss. Upon opening the hood, I was shocked to see steam rising from the wiper fluid reservoir -- which was filled to the top with the very hot, "lost" coolant!

The coolant expansion tank was also sort of buzzing, as if under high pressure -- or perhaps negative pressure, and I additionally noticed saw that the plastic tube on the passenger side edge of the hood that feeds the washer jets was ruptured.

Before I pull out the tools, is the following diagnosis correct? :

I assume the washer fluid heating coil is ruptured as well, and I will try to fix or bypass it. This would explain why, when I refilled the washer reservoir about a month ago, I lost about 75% of it by the next day -- with no leakage to the ground. I assume it was sucked into the cooling system, and coolant was also being pumped back into the reservoir -- accounting for the unusually oily streeaking when I would use the washers.

From reading various threads here it seems bypassing the washer fluid heater coil is no big deal, but before I do that, is there anything else I should be considering?
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2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black

Last edited by EricSilver; 02-09-2003 at 05:08 AM.
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  #2  
Old 02-09-2003, 08:46 AM
ILUVMILS's Avatar
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Why not replace the heating coil instead of by-passing it? MB goes to great lengths' to ensure a clear view. Did you know that there is a bladder in which coolant flows beneath the windshield at the bottom. This keeps the wiper from freezing to the glass. MB's also have electrically heated nozzles and washer hoses. Your leaking coil is part of a system. Replace it and keep the system intact. Good luck
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  #3  
Old 02-09-2003, 09:44 AM
DHA DHA is offline
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Hot Coolant in Washer Reservoir

A suggestion, before you bypass or remove. Check with Phil or your local MB dealer whether Part number 126-830-07-84, the thermovalve in the washer tank, is standard for your car. Read the thread "170 degree washer fluid" and ignore the side comments. It sounds as if either the named part, or the stainless heating coil itself developed a leak, allowing coolant to enter the washer reservoir, etc. etc. Cheap part, ca. $35
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  #4  
Old 02-09-2003, 03:05 PM
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The Plot Thickens

OK, Here is what I have discovered.

With Heater OFF:
Coolant Back-Flows into Washer Fluid Reservoir
If I remove expansion tank cap, back-flow is very rapid.

WIth Heater ON:
Washer Fluid Reservoir Drains into Coolant system.
If I remove expansion tank cap, drainage is very rapid.

After Engine Shut Down:
Some limited coolant back-flow into washer reservoir, and sucking sounds at expansion tank.

The washer fluid heater coil is fine. A cylindrical object -- perhaps DHA's mentioned thermovalve?? (SEE PHOTO) that it connects to is the apparent leaky culprit, as it is where I see the back-flow/drainage occuring. Or perhaps it is where that object connects to the external hose/tubing.

So, by not keeping the heat on, I have unwittingly been draining my coolant.

So, how do I remove this reservoir, coil, and Thermovalve. It seems like an easy fix, even if I need to buy a new part or two.
__________________
2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black
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  #5  
Old 02-09-2003, 03:07 PM
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Photo Didn't work

Here's the photo:

Note the dirt and coolant residue in the tank.
__________________
2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black
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  #6  
Old 02-09-2003, 03:14 PM
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This photo shows the back-fill after about 90 seconds when heater is shut off. Reservoir is 1/3 full.
__________________
2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black
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  #7  
Old 02-09-2003, 04:45 PM
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Just by-pass it till you can get a new part. I have by-passed all that I have seen failed, but here in Florida it's a pretty useless concept.
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Continental Imports
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  #8  
Old 02-09-2003, 06:55 PM
EricSilver's Avatar
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Hi Steve,

It's done. I'll replace the coil when I get around to it, which will probably be never.

Using the "Upper Hose Squeeze Analysis Method" the coolant system pressure appears to be back where it belogs. Before, I was able to really squeeze the hoses; now I can't.

Also, should I expect to see some increase in exhaust steam, given that coolant system pressure has been abnormally low for about a year and some head gasket leakage seems likely until the natural seal re-forms? (That happened once before under different circumstances.)
__________________
2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black
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  #9  
Old 02-10-2003, 01:10 AM
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ILUVMILS:

Thanks for the info. During the overheating, I was able to hear a hissing sound from the dash just under the windshield, which I presume was steam entering the bladder. The heater core was making more of a sputtering noise, like what you hear when you sprinkle water onto a hot frying pan.

DHA:

Seems you nailed it. The thermovalve, or its connection to the washer reservoir tubing, is undoubtedly the culprit.

I'm going to go ahead and replace it now rather than wait, since I have a feeling I;ll need warm washer fluid before winter ends.

I just completed my stress test of the (temporary) bypass: Drove from Fairfax, VA to Capitol Hill in Wash. DC & Back, a trip that normally causes considerable heating. The coolant temp never exceeded about 84 -- which is almost unbelievable. It always creeps close to 95/100 in Wash DC Driving.

Thatnks again for your help.
__________________
2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black
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  #10  
Old 02-10-2003, 01:43 AM
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Per ILUVMILS's comment on having the heated windshield washer fluid working, I have found that even in the summer it is a great feature.

With the right ratio of WWasher fluid and water, smashed bugs come off the windshield a lot easier.

Haasman
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'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
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Last edited by haasman; 02-11-2003 at 10:21 PM.
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  #11  
Old 02-11-2003, 10:09 PM
ILUVMILS's Avatar
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BUGS!!! I never thought about bugs! I was in Georgia a few summers ago and I couldn't believe all the bugs on my windshield. Another good reason for keeping the heated washer fluid system fully functional!!!
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  #12  
Old 02-13-2003, 04:58 PM
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Speaking of bugs, I took a (night) drive from Fairfax to Front Royal, VA two summers ago. After the return trip, there was a mat of insects -- some previously unknown to man -- plastered to my lights, grill and windshield -- so yeah, a spritz of hot washer fluid is essential.

Speaking of washer fluid, it's been four days since I bypassed the heating coil. Half of the water I filled the washer reservoir with has leaked through the bottom-center of the tank, forming some rather nice looking icicles on my front bumper. Are there step by step instructions for removing this tank and its contents?
__________________
2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black
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  #13  
Old 02-13-2003, 05:22 PM
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Eric,

I changed the 300E's several months ago. Pretty straight forward. There is a black plastic hold-down knob that is a good place to start, after removing the windshield washer pumps (they wiggle straight out I recall, the coolant level electrical connection and finally the 'w.washer heating loop'.

On a previous car, I had good luck sealing a washer tank with silicone. I cleaned up the area first with some steel wool. It held for years.

Haasman
__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
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  #14  
Old 02-13-2003, 06:51 PM
EricSilver's Avatar
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Location: Fairfax, VA
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Haas,

Thanks for the scoop. I'll tackle that this weekend.
__________________
2001 E430 4matic
122,xxx miles
Black/Charcoal Interior

------------------------------------
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black
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  #15  
Old 02-13-2003, 08:17 PM
ILUVMILS's Avatar
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Eric, find out if the washer reservoir is available as a complete assembly. It will include the heating element as well as a new pump and grommet, assembled and ready to install. All ML reservoirs come this way from MB, so it's worth seeing if this is available for your car.
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