everytime i drive my car i hear like this whistle noise comming from my engine. i also notice that my car does idle very rough and once my engine is running the car also drives really slow as its got no speed and it sunds like my car is going to die would this be a vacuum leak ? my other problem is last time i parked my car i heard a sizzle in the engine bay i took a look and it was dripping coolent everywhere also was dripping inside my engine. i have got advice from mechanics and friends and so on but im not getting proper answers would anyone be able to tell me what could be happening here ?