yup sounds like a heater core! have fun replacing it. like foxbody said, inspect it real well! i didn't do that when i changed mine, and the new one leaked worse then the original one! but i tell u taking the dash apart the second time was a snap cause i already knew what to do, took me like 45 minutes instead of over 2 hours the first time.
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89 GT AOD w/ shift kit, B&M rachet shifter, Trickflow intake, Crane (E-type) cam, 70Tb, 75MAF, 1.6 Rockers, Pulleys, MAC headers and H-pipe, Dynomax mufflers, K&N, 3 core radiator, white face gauges, custom interior, cobra R rims
MY89GT