"Wayne.B" wrote in message
...
On Tue, 23 Mar 2004 07:13:02 -0800, "Lloyd Sumpter"
wrote:
Is there a bypass that shunts some
of the coolant around the HW circuit? If so, how does ANY water go
through the
HW circuit? Is there some sort of valve?
========================================

Yes, the HW heater is on a parallel loop. In a car it's flow is
usually regulated by a thermostat as I understand it. The thermostat
opens and closes depending on temperature setting. Most, but not
all, of the coolant flow will take the path of least resistance, just
like a parallel electrical circuit.


Thermostat only makes the water warm. On a car and my boat, the waterpump
has an outlet for the heater. this is the return from the heater core. Out
of the intake manifold is an outlet for the ho****er feed to the heater.
Just changed the waterpump on wifes Blazer and this is the way it is.
Lloyd, look at your S10. Off the high pressure side of the waterpump is a
feed to the heater and on the suction side of the waterpump is a return
line.
Bill