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Old 06-13-2012, 12:21 AM
cbjukraine cbjukraine is offline
'84 300D Owner
 
Join Date: Oct 2006
Location: Dallas, TX
Posts: 211
Quote:
Originally Posted by w123love View Post
The temp switch is for turning on the coolant pump once the car is up to temperature in order to circulate coolant, the valve has something to do to that. One can ASSUME that when the rack is advanced and the RPM’s go up, it actuates the valve and lets coolant circulate even if it is not up to temp.
This isn't even close to correct.

There are two switches on the thermostat housing on the 617. One is the electrical cold-engine lockout switch that keeps the climate control system from operating before a certain coolant temp is reached, the other is the mechanical EGR vacuum switch. The EGR doesn't begin working until the engine coolant reaches a certain temp because the vac switch doesn't open until the coolant is warm. I forget the exact temp.

If the engine is running and all is operating properly, coolant is always circulating through at least the block and head, being moved by the water pump. When the engine is hot, the thermostat directs some coolant to the radiator for cooling.

Unless you are referring to the auxiliary coolant pump, but that only works when the heater is on to circulate hot coolant through the heater core at idle.
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cbjukraine
'84 300D
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