Mitsubishi Repair: Squealing noise in Engine TJ 2001 Magna Manual, car trips, short trips

Question
Hello. For the past 4 months, I have been hearing a loud squealing noise in the engine whilst I am driving that occurs sporadically or intermittently.  This makes it hard for a mechanic to work out what it is, because it doesn’t happen all the time. The squealing noise sounds like it might be a belt, because when I turn the (engine off) the squealing noise winds down. It never happens on short trips (i.e. 5 mins driving), rather longer 15 minute plus car trips. During the short 5 min trips, the speed limit is 60 km/h and the squealing noise does NOT occur, only when I am on a 20 min trip where I travel up to 80km/h. When I turn the engine off, and let it rest for 5 mins and start back up again, the squealing will eventually come back, but not straight away. What could be the issue? Loose belt of some sort? Thanks.

Answer
Paul,
Definitely check and replace the belts if necessary.  Most belts need replacing around around 160,000 km or so.  There's also a chance that the bearings in one or more of the belt pulls or A/C tension has become excessively worn.  Have those checked as well.
Good luck!