If this is knackered can it cause white smoke from exhaust? I thought my head gasket had gone but ive got no mayo on oil cap, nothing on dip-stick and the coolant is oil free. I have noticed alot of wet around the CTS though so im gonna replace it. Is it worth going to audi or is there a better aftermarket option? Also it is using a small amount of coolant - but nothing major over the last 290 miles.