Rigsby

I've got a 96 wrx, had a few problems with leaking a little water onto the exhaust manifold, somewhere on the right hand side of the engine as you look at it from the front, just needed a top up every week or two so never really been too bothered. Now suddenly there was loads of steam coming out of the car when I parked. This time it seems to be seeping out from the header tank?? its on the left side of the engine, with the orange sign saying dont remove when hot. The water seems to be coming from all around the seam of the tank where theres a crome strip. Any ideas whats happening? Please!!