Couldn't find this one in the archives. Changed the master cylinder yesterday. Today I had a small puddle (tablespoon) of antifreeze in the skid plate. Anti freeze on the top driver side (North America) of the engine behind the intake. Appeared to be right under the black pipe running between the engine and the heater and puddled into one on the casting depressions. Sort of near where the pipe bracket bolts to the engine. I started the car, checked, wiped of the anti-freeze. The rest evaporated, now nothing. I let it cool and restarted later. Still no anti-freeze. I checked the hose clamps and they were tight. Can those pipes rust through? Leak back where they attach at the engine? Anyway I couldn't find any dampness anywhere. Any advice? Did I maybe just wiggle the heater lines while wrestling with the Master Cylinder? Thanks

I think you got a pinhole leak in one of the heater core hoses (going from the water pump/intake to the firewall) The OEM subaru hoses are actually pretty crappy hoses. They are very thin walled compared to the heater core hose you get at a parts store. probably poked the hose with a screwdriver or something and made a lil hole. top off the coolant, start the car up, let it warm up to operating temp and then squeeze/bend the heater core hoses.

 

Wear safety glasses.. Antifreeze burns like hell and it will spray out if there is a pinhole and you get the hose flexed the right direction.