It probably would not be a bad idea. The system could have lost up to 30 per cent of its gas. A forthcoming problem is the EC’s new insistence on a new a/c refrigerant called HFO1234yf that is supposed to be even more environmentally friendly, but is hugely expensive and Mercedes-Benz says it could constitute a fire risk. More at: www.ac4cars.co.uk/r1234yf.html