The PHH is the "pesky heater hose" that is located on the left rear of the engine, down low, just above the starter.
It is known to fail from the inside out. It can start as an annoying coolant loss because you can never find it because a cool engine may not drip because the hose does not...
Regular coolant loss is only by a leak or a HG.
It took me 3 months of regular checking to find my coolant loss and it turned out to be the 3 o-rings on the bypass pipe by the thermostat.
I happened to catch a bit of coolant before it evaporated to define where the leak was occurring.
I...