Can this expert community let me know if the Windshield Washer reservoir heater on this car is thermostatically controlled?

If so, what are the conditions that would enable engine coolant to flow to the coil in the washer reservoir.

The Operator's Manual only notes that the washer reservoir is "automatically heated".

As a note, engine coolant flows thru the reservoir coil all of the time in the 1995 E320.

Thanks.

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Tom Latos
2002 E320
1995 E320 Sold at 288kmiles

I'm fairly certain the the thermostat is the plastic part of the heater coil inside the bottle. I have no idea at what temp it operates. I can't say that I have ever seen a problem with one.

Why do you ask?

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Mercedes Benz Master Tech - Retired

my 95 has that washer heater and its heating coil has the thermostat built into it.

The washer fluid is always maintained at about 35 to 40C from that thermostat. When it goes bad the failure usually results in boiling of the washer fluid.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)