incidentally, I had a situation where a vane has broken off (like yours are about to), laid up against the inside the housing, and occasionally was spun around the inside. Sometimes it would get stuck over the intake port, nearly blocking it completely, then free it self and get stuck somewhere else.
Result: intermittent overheating
. Caused a real head
scratcher. Sometimes there would be water in the exhaust, sometimes not. From this experience, I install new impellers every 100 hours.