Given the age of the vehicle, might be time to replace the heater hosed and the plastic "T" fittings at the firewall assuming your have rear a rear heater core. The plastic gets brittle over time and will let go typically without warning. Just recently replaced all of mine, the one near the AC compressor had a very slow drip that seems to have caused the AC clutch bearing to start to tweet like a bird! Not looking forward to replacing that.
Beware, the Dorman replacement T's and quick fittings are sized a bit incorrectly. I had to open up the inside of the quick connection with the finger releases on my truck to slide over the aluminum stub pipes, what a PITA!
Beware, the Dorman replacement T's and quick fittings are sized a bit incorrectly. I had to open up the inside of the quick connection with the finger releases on my truck to slide over the aluminum stub pipes, what a PITA!