“mechanic…suggested she replace the belt (I guess serpentine belt)”
You shouldn’t be guessing, because he may have been talking about the timing belt, and ignoring/postponing that type of maintenance can be…very costly.
IIRC, Kia specifies a timing belt replacement interval of 5 years or 60k miles, whichever comes first. On that basis, while you are coming up very soon on the 60k mark, you are about 2 years overdue on the basis of elapsed time–which is just as important as the odometer mileage factor.
If this engine is of the “interference” type, when the timing belt snaps (with no warning whatsoever), pistons and valves will collide and lead to very expensive repairs.
Even if the engine is not of the interference design, when the timing belt snaps the engine immediately stalls, you lose power assist for the steering, and there will only be enough power boost for the brakes for one hard stop. Imagine if that happened…at turnpike speeds while amongst 18-wheelers…or while crossing RR tracks…or while driving through a very dicey area late at night.
All of this is why timing belts should be replaced proactively by following the mfr’s guidelines. To do otherwise is…foolish…and not cost-effective, to say the least.
So…I strongly suggest that you clarify with the mechanic whether he was talking about the serpentine belt (which powers the alternator & A/C compressor), or whether he was talking about the timing belt.
If he was actually talking about the serpentine belt, ask him to point out the problem that he has observed with it. If he was talking about the timing belt, say your prayers that this overdue maintenance will not result in “big bucks” repairs before you can have it taken care of.