Fat model PS2 grinding Noise

I own one of the fat PlayStation 2 consoles and every now and then, it lets off a loud grinding noise when reading a game. It doesn’t happen on every game however, there some games where the ps2 reads the disc a lot more quicker than other games yet as those discs are being read, a loud grinding noise starts and the game completely freezes. Only after I restart the console entirely the noise disappears. It’s not the games as most are resurfaced so it’s something to do with the rails holding the laser lens. Any idea what it could be?