Sleep mode and the Fan

Hello everyone

My Macbook Pro started making loud fan noises about 5-10 minutes after activating Sleep Mode. This started some time last week and naturally, I began to get worried that it was a sign it would crash or something. But the thing is, once I out the laptop out of Sleep mode, the fan noises stop and my laptop operates normally. In fact, it remains cool throughout Sleeping, so it doesn't overheat or anything like that. I also discovered that the noise doesn't occur sometimes, and it Sleeps normally but most of the time the noise comes.

What do you think is causing this and how could I stop it? I have tried resetting the SMC but the problem still continued.

Thank you very much 🙂