The former Netherlands man believes the Manchester United boss needs time to make his new signings gel - but warns that even that could not be enough.
The former Barcelona manager, who holds an infamous rivalry with Van Gaal, says the Man United boss needs time to fix together a 'new team.'
But, even then, Cruyff believes United will find it tough to make high-earning stars like Radamel Falcao blend into a squad already full of star players.
When asked if he thinks Van Gaal will succeed at Old Trafford, Cruyff told the Guardian: “We hope so because it would be good for Dutch football and other Dutch managers. But how it will go? You never know. It will take time.
“I don’t know because they almost bought and created a new team. So now you have to fix it together – the team itself. It’s not a question anymore about the quality of the players, or are they good enough. But to make a mixture of good players is very difficult.
“They are all famous. They earn a lot of money both on and off the field. How can you create a team and bring all these egos together? The main goal for Manchester United is for them to play well – and not have a player saying, ‘I play well, I scored two goals’.
"Because if I score two goals but three goals go into our net then we lose. They provide [Van Gaal] with a lot of good players but he has to turn them into a team. And you can’t arrange the chemistry of the team in two weeks. It needs time.”
United host Queens Park Rangers on Sunday in what will be their fourth Premier League clash of the season.
From their first three, Van Gaal's men have failed to register a win, with just two points to their name after a defeat to Swansea City and draws with Sunderland and Burnley.