I normally hear hissing from the right side of the engine when i start my car. The aircon doesnt work so i first ignored the hissing but now its growing louder, i thought that the hissing might be coming from the aircon pipes. I tried to locate where the hissing is coming from by just inspecting when the engine is on, but cant see where exactly. Its a right hand drive by the way. Can this be a vacuum leak?
It could be vacuum leak. While the engine is idling, spray some throttle cleaner in places where you hear the noise, and if the engine noise changed, you will definitely have a vacuum leak.
You can also use cigar as Scotty shows in this video.
Thanks Yaser, will do that
The hissing noise is your car telling you it's about to bite you, for $$$$$.
