Climate problems

Hi,
has recently had a 90s V8. The car is top except for a little something
(I hope that it is a little thing). The climate makes strange
Noise. When I run it to normal or hi, a sound similar to the start of a 747 comes after a few seconds. On
low the sound only comes after several minutes and also not so loud.
I've got a suspicion that it's a little loose. When I shut down the climate briefly
And then again, it's short gone.
Can somebody tell me what that might be about? is it possible to get it back without a workshop???

Thank you very much.
Greetings Dani