next time it squeals check the voltage on the battery, if its around 12ish while it squealing then it the alternator belt. When mine used to do this i checked the voltage on the battery and when it would squeal the voltage would dip below 14v, and when it would stop voltage would go back up to 14volts. Its really simple to do, just do it next time u do an oil change or whenever the car will be jacked up or on ramps.