Soooo. I have been getting a small coolant loss, 1 litre every 1000 miles or so. The low level light has never come on, the heaters are up to temp and the climate works, never gone above 90*. Today on the way home I had a slightly weird experience, with gently pulling away in first the car went like **** then I backed off, I never asked it to go like that but it just took off. After this the car felt slow, and I was convinced I had a boost leak and the car had over boosted. I popped the bonnet and it was hot as **** and the coolant tank was bubbling and had nothing in it. I gently let off the cap and all hell broke lose, the car threw about three litres of boiling coolant out. Very strange. I refilled and started the car and heard a chattering from the bottom end, immediately I suspected the water pump had sheered. But then I remembered it is a metal one :/ There is no flow in the header tank, the water is just stagnant. There is a little mayo in the filler cap for the oil. I took the car for a short drive and it feels down on power until you give it full beans, then it is fine. Doesn't over heat at all, blowers on or off. So, any suggestions?