ps374

Does water flow through the heater core on a 84 when the switch is in the closed position?

suks2bu37

On every car I have ever owned, when the temperature is set to cool, the heater control valve closes and does't allow the hot coolant to go to the heater core. I have seen more clogged up heater cores due to lack of usage. I worked at a dealership and was told by the service manager to turn on the heater once a month and let it run for at least twenty minutes to circulate the coolant through the heater core. If your heater doesn't work in the winter, I can tell you from experience, that you need to take the heater hoses off the heater core and flush water back and forth through the two nipples. You will be amazed at the slime that will come out and your heater will return to its proper heating temp. I have actually seen the heater core so plugged, it wouldn't run water through it until I reverse flowed it with about 30 pounds of water pressure. The slug of slime that came out could be picked up and thrown across the shop. Just my .02.
suks2bu37

AGENT 86

It shouldn't. There is a vacuum operated valve, just before the core.