I've recently started getting a swoosh air sound from the engine compartment when changing gear, sounds exactly like the noise you get after installing a dump valve. It's usually only noticeable within the first few minutes of driving (higher rpm while auto choke is on). Is a pipe or seal loose? Or broken? What should I look for? 1.2 engine.

Also is there any reason why I seem to get a loud rattle from the engine during acceleration when I put the AC on? Does the AC put more stress on the cam chain? Or is it purely driven by the auxiliary belt?

Thanks.

Air con needs re-gassed.

Air con needs re-gassed.

Air con has been re-gassed recently with added dye and the system was leak tested and no faults were found, the AC works well as the air from the vents is freezing. The rattling noise from the engine is only there when the AC is on and the engine is under load, if the AC is on and the engine is idling it's fine, if the AC is off it's fine all the time (no rattle noise).

Will probably just have to live with it, could just be the cam chain getting noisier under load...