RC 9/12/2012Sounds like the heater core is leaking.
RC 9/12/2012Replacing the heater core is not an easy DIY job (7 hrs).
rick 9/12/2012Replaced heater core on Chevy Astro van I had years ago . Think it would have been easyer to take the motor out and go in that way . Ha ha . Good luck AND take your time . One thing that helps is take some photos as you go , even with your phone and keep something to put nuts and bolts in . Sucks looking for them in drive way .