Heater Host Shut-off Valve

The NAPA number for the manual 5/8" cut off is 660-1414. If those of you that dont think you need two. Put one on the side it goes in and take the hose off the other side and start the motor. It will back flow. We use two on every system that comes in in the summer where people complain about the A/C not cooling good enough. Those cutoffs are good for another 10 degree's of cold air. :nice:
 
bud4660 said:
The NAPA number for the manual 5/8" cut off is 660-1414. If those of you that dont think you need two. Put one on the side it goes in and take the hose off the other side and start the motor. It will back flow. We use two on every system that comes in in the summer where people complain about the A/C not cooling good enough. Those cutoffs are good for another 10 degree's of cold air. :nice:

You don't need 2 HCV's the water can not flow threw the heater if one line is shut off. IF you think it can, turn your blower on and feel the air coming out, then close the valve and you will loose all the heat very quickly. It's simple science. The amount of convection heat transfer you will get threw the open hose is next to nil. You will never find a vehical that has 2 hcv's on it, never.
 
The factory uses one on AC cars. No heater cores blow up, and hot coolant can't get into the core as the valve doesn't allow any of the cold coolant out. There may be heat creep over time, but it's kind of a non-issue.