When i first drive of in my Volvo it is fine then after about 6 miles when i turn corners there is a horrible wining noise coming from the engine or power steering it is worse when the car is turning corners slowly i have changed the belt but no better the fluid level is fine but i have noticed it is weeping out of the filler cap onto the top of the reservoir and i have to wipe it clean after every journey any help would be much appreciated i can do most work myself.