The hose is not an air hose is oil delivery and should not collapse that way...my recommendaion is to have it replaced, porsche updated that particular hose in 2001 making it stronger and the inlet that goes in the engine deeper to avoid any possible leaks. One question regarding the noise, is it a constant sqeal ( which may indicate belt ) or is it intermittent, does it squeak faster/louder as you accelerate, if you stand by the rear wheel on the passenger side with the car on idle, does the sound feels like it's coming out of the engine block? If the answer to these questions is yes, you may be looking at the ugly end of a flywheel problem.....Have the car lifted and inspected from underneath while the squeak is happening, that should tell you better....God luck..
