Is the AC throw less or cooling low?
For throw as mech 1 said get ac system serviced, if its the cooling and air throw is ok, just top up the gas.
Mileage you quoted is ok for bombay city driving.
Also do ask the mech what he meant by engine tubes and post here which will help.
__________________ The strength to change what I can, the inability to accept what I can't, and the incapacity to tell the difference. -Calvin |