Oil in the coolant

So as the the title says i had oil in my coolant. Ive got the engine torn down now because i had someone at a local shop test my oil cooler and say is was ok. Ive checked the head gasket and it looks to be in good condition. Im curious does any think the guy at the shop may have messed up in testin the oil cooler? Is there any other possible places oil could get into the coolant? could the block be cracked? Initially the dipstick looked too be fine when i checked it before tearing the car apart. The car is a 2002 225 amu engine.