JoelP

I once had a loose heater hose clamp that allowed coolant to flow across the heater core tube and inside the housing. Check your clamps...

See below. It was leaking from a hose, but not when hot so I initially failed to see the hose leak.

I had it pressure tested and surprisingly it passed the pressure test. The surprising thing is that one of the hoses leaked that was...

I noticed that my coolant level dropped significantly after each trip. Then I saw that coolant was dripping from the housing that...