My AOS never gave me a problem until it started squealing after the engine warmed up. I had no oil being sucked up and smoke from engine and it ran perfect. When I replaced the AOS, I saw that the boot on the bottom was nearly collapsed. This is why the squealing noise was being made because it was sucking air through the front crankshaft seal. The AOS will come with the boot and seal. You do not need to replace the tubes.