There are two clear issues here:
(1) A vehicle must be fit for its purpose; in legal terms it must be "mercantible". Certainly, a vehicle without a functioning engine is not fit for any purpose - other than for a sale to a museum. Hence, if it's only been two weeks, it would seem that it never should have been sold UNLESS you did something to deteriorate the engine significantly in that short period of time.
(2) Typically, there would be a warranty for something like this at the time one purchased the car.
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