2002 E320 Windshield Washer Reservoir Heater
 

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.

Waher Solvent Thermostat
 

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?

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.