dmel

Lately the car has developed the following symptoms.

When pushing the engine for a while and it gets hot, a funny smell (it stinks) comes from the engine bay.
At this point, when turning the steering wheel, the normal power steering pump whine can be heard twice as loud. Steering wheel feel and assistance unchanged.
Finally, at a track day, an amount of power steering fluid escaped from the top cap (where you add fluid to the system).

When the car cools down again the symptoms dissapear. Could I have contaminated fluid? It is like the fluid is boiling when getting hot. Could I have a knackered pump? Is it possible that the pump has problems only when hot?

Help would be much appreciated.
Dimitris MY99, 45K