Rooney was reacting to United's defeat at Brentford on Saturday.
He said on his personal podcast: "I have tried my hand in management and it didn't work out too well, I get it. Ruben Amorim is my age, he is still a young manager and I'm sure he still has a massive future, but what's going on at Man Utd, this is not Man Utd.
"I honestly hope he can turn it round and he does. But if you're saying to me, 'do you believe he will?', then, after everything I've seen, honestly, I've got no faith in it.
"I don't recognise the whole football club. I don't see players fighting, I don't see character, I don't see desire to win.
"I go to a game watching, expecting, here we go again - expecting the team to lose or maybe pick up a point.
"It's not even just results on the pitch. It's everything about the club that needs fixing - Jim Ratcliffe and Ineos have walked into a real challenge.
"We're seeing staff members getting sacked after 20, 30 years who are very important people to that football club.
"The soul has gone from the club. It needs a new engine, a new lease of life. It needs something to kickstart that football club."
Kai concern
Rooney also concedes he has concerns about his two sons inside the club's academy, including eldest Kai, who at 15 has been playing for Darren Fletcher's U18s this season.
He said: "I've got two kids at that football club and I really hope this doesn't affect what they're doing. What I'm seeing at that football club is not Manchester United."