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Old 02-27-2011, 11:40 AM
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JimFreeh JimFreeh is offline
Benz addict
Join Date: Mar 2007
Location: Hampton Roads, Virginia
Posts: 3,366
Originally Posted by stormyc88 View Post
Bypassing the pump shouldn't hurt anything, especially since you're bypassing the heater core altogether, and since since you're bypassing the heater core, engine temperatures should act the same as if you were running with the heater off.

Yes, and no.

Pump has no effect, but you're also bypassing the monovalve, which stops flow when the heater is off, so you introduce a short circuit for hot water.

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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