Date: 29 Aug 2006 13:38:00 -0700 From: "yaofeng" <yaofengchennospaml.com> Subject: Re: 2002 Saab 9-5 cracked heater valve
Kevin Rhodes wrote: > In article <1156783514.006972.122460nospam2000cwp.googlegroups.com>, "yaofeng" <yaofengchennospaml.com> wrote: > > >I don't know anything about the 9-5. Are you sure it has a heater > >valve? If there is a heater valve on the 9-5 it is indeed going > >backward. The c900 has a heater control valve. It is a mechanical > >device to regulate coolant flow into the heater core actuated by > >control inside the cabin. Any c900 owner knows the heater control > >valve is notorious for leaks. SAAB recognized this and changed the > >design in the 9000. The 9000 colant circuit for heating the cabin has > >no valves or any mechanical device to regulate coolant flow. Instead > >the heater core is enclosed in a box. Cabin temperature control is > >done by regulating air flow throught the box. Although the heater core > >still goes bad and leak the robustness of the design improves > >significantly over that on the c900. > > > >Maybe someone can clarify if indeed the 9-5 has this feature. I rather > >doubt it. > > > The valve in question does not control the heat to the cabin, it shuts the > coolant flow off completely. It is either on or off. This is so that the A/C > does not have to cool off heated air when the A/C is on full blast. You can > bypass the valve with a piece of pipe and you will likely never know the > difference - you would just have slightly warmer A/C on the coldest setting. > The valve is actually used on all sorts of GM vehicles, and costs ~$40 from > Cadillac dealers, as they sell just the valve. Saab sells the valve plus all > the attached hoses for ~$300.... > So the 9-5 HVAC design is indeed going backward? The valve whether shuts off or regulates coolant flow introduces a source of coolant leak just like the c900. On the 9k although coolant is always circulting in the heater circuit it doesn't hamper flow of cold air if only AC is desired. The heater matrix sits in a box with flaps. The flaps are closed when full AC is on demand.