Loss of suction, loud blowing noise

\015 When I turn on my Dyson is seems okay for about 5 seconds then it starts making a loud blowing noise. The blowing is coming from the small vent on top of the canister (underneath the handle) and also from around the base of the canister (where it attaches to the vacuum), both areas are blowing hot air. It still picks up some things, but there is a great loss of suction..I’ve cleaned the filters and checked for blockages..Any ideas???\015 – Dyson DC07 Bagless Upright Cyclonic Vacuum