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Old 08-13-2016, 09:53 PM
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JimFreeh JimFreeh is offline
Benz addict
Join Date: Mar 2007
Location: Hampton Roads, Virginia
Posts: 3,366
W140 S500 overheat, lost coolant

Whilst driving to work Friday morning, my low coolant light came on. I wasn't too concerned, figured I'd look at it after I got home.....

I left early for my chemo appt and saw a nice puddle under the front of the car. Figured I'd keep a close eye on the temp gage. Got about 2/3 of the way when the temp ran into the red zone. Pulled into a convenience store and bought a flat of bottled water. That got me to the docs. After chemo I refilled the bottles, then poured the water into the radiator. That got me home.

Since there was no smell from the vents, I assumed the heater core was sound.

An examination of the radiator and engine compartment revealed coolant under the master cylinder.

To see further, I needed to remove the cowling and the wiper assy.

Still could not identify a leak in any of the Medusas hair nest around the booster and master cylinder. I noticed that the heater return line was getting hot and that I was getting water leakage under the car.

Turns out the wiper deicer had sprung a leak, and was leaking behind the firewall into the cavity that contains the m/c.

Tied off the hoses and all is well.

BTW, the W126 chassis has this "feature" as well.

14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles
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