My car was making a

my car was making a squeaking noise must all the time in the morning,we took the car to the mecanic and they changed the reservoir tank hose, because he said that was liaking, and still was doing the samething, and he was loosing the antifreeze, coolant an yesterday they changed the driver belt for the altenador but today did the same noise,and we change to the reservoir tank cap the car was not over hesting but yesterday was and he said that was because he did not release the air from the reservoir hose