Q: coolant leaking on 2001 BMW 330i

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
noticed 3 weeks ago water spots under car which turned out to be coolant was determined that the water pump needs to be changed. after water pump was changed 3 days later it started leaking again. this time it was said that it was coming from thermostat housing so that was changed. one week later that is today low coolant light came up as i was heading home. i turned onto my driveway and when i got out noticed the long drag of coolant all over. i let the engine cool and started to refill radiator with coolant. i noticed that as i was pouring in the coolant it was coming out on bottom like if there was a hole. what is the possible problem here?
(1) Answer
A cracked expansion tank or radiator, plastic cooling system components exposed to constant heat cycles causing the material to decay over time. Also the introduction of new coolant also does lead to possible further leakage