URGENT: Oil Leak

[thirdstreettito]

My 88 had a small oil leak, maybe 10 drops overnight. Then one day it went to a puddle when it was idling warming up. So I went through my day and called my mechanic, next day at 9 am I went in, truck had lost 3/4 quart of oil in that 24hr span. So he looked under it, it was where the oil cooler/filter housing bolts to the block. So I went to AutoZone and got an O-ring/gasket set for it and he took it all apart and scrapped the old stuff out and put the new stuff in. I also had him change the oil and put in NAPA(valvoline btw) 5w30 and a NAPA Gold filter. I checked it almost everyday for the next week. Then yesteday I started the truck and let it warm up, I walk outside and theres the same puddle! I called my mechanic and he told me to come in 9am Monday. Any ideas guys? I need this fixed ASAP. Could it be the housing? Thanks, Bradley