On Jul 20, 12:34 pm, "maxpower" > wrote:
> "Ted Mittelstaedt" > wrote in message
>
> ...
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> > "dprkk" > wrote in message
> ups.com...
> > > After living with lukewarm heater performance for too long with my 91
> > > GC, I decided to get to the bottom of the problem. I found no vacuum
> > > to the heater core control valve. The vacuum line goes into the
> > > firewall to the under side of the dash somewhere. What is the
> > > suggested way to start troubleshooting and taking things apart under
> > > the dash? TIA.
>
> > With a 15 year old vehicle you might consider bypass rather than
> > repair. For little money you could run a vacuum line from manifold
> > to a vacuum valve you just mount under the dash and manually
> > operate. Run a line from the valve to the heater core control valve.
>
> > Taking the dash apart is a very complex operation. The first step
> > is getting the factory service manual and studying the procedures.
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> > Ted
>
> You DON'T need a vacuum hose from the dash to the control valve!! The
> purpose of the vacuum hose is to close the heater control valve when max air
> is requested. Apply a vacuum source to the valve will cut off all incoming
> hot coolant to the heater core.
>
> Glenn- Hide quoted text -
>
> - Show quoted text -

Thanks to Glenn, Ted and others for the advice. I understand how this
valve works now. I bought all new radiator and heater hoses and will
rip everything apart tomorrow. Hopefully after flushing the core a
little, the heat output will improve. Also bought a new t-stat from
Dodge. Two last questions; to flush the cooling system, can I just
open the petcock drain and put a garden hose in the top of the
radiator and let it circulate? Also, I hear about air in the system
causing problems and to "burp" the system. Just how do you do this?
Thanks all.