911E is right, it's for the AC, the one in the wheel well is not stock, the stock one is a "trombone" cooler, (bunch of tube in loops), so I'd say that one was put in by a PO. The Carrera style has a fan in front and more closed in.
Your's looks like it has some leaks in the couplings.
Wayne's book would be a good investment for the DIY'er.
