low collant light on

You will need to have a cooling system pressure test done to determine exactly where the coolant is going https://repairpal.com/estimator/chevrolet/impala chose cooling system leak test and you can locate a shop here to perform the test https://repairpal.com/chevrolet-repair-in-raleigh-north-carolina But I think these intake manifolds have problems with leaking gaskets

had the same problemwith my 02 chevy impala v6, I filled the radiator twice & kept over heating. Brought it to the shop had it pressured tested for leaks, nothing finaly came to find out that my intake manifold gasket was bad. Replacement $375.