My belt on my a2550 is slipping and has a loud screeching noise. i tightened belt, but still not working

Sounds like the orifice (expansion Valve) is plugged , resulting in a stalling of the compressor, screeching is the belt slipping.

No idea

Need the car to find out

Check the drive belts or serpentine if there is only one. sounds like one is slipping.

Do you know if you are tightening it correctly?
Both bolts at the back of the walking belt should be turned clockwise to tighten the belt. You must also tighten the bolts the same amount and typically no more than 1/2 turns at a time. I usually adjust belts while the machine is running at approx 3 mph. Your belt should be just tight enough to not slip when you walk on it. If its too tight you'll wear out the motor bearings.

It is your serpentine belt slipping on one of the metal pulleys and the friction is causing the high pitch screech. The belt may need to be tightened or replaced, which is an easy fix.

It sounds like you have a belt or pulley problem, or possibly a bad bearing in the alternator, or water pump. I would suggest, having it looked at, by a mechanic right away.

The screeching noise is probably the belt slipping under load.
I would start by replacing the belt, and if it happens again, then it is probably a tight bearing or similar on the pump, that is causing the problem.

The blower is located under the passenger side however, the screech in the engine are is most likely a lose belt. Tighten or replace your belts and teh sound should go away.

One of the belt pulleys likely has a bad bearing. watch the pulleys for binding while it's running or remove the belt and check each pulley by hand. AC puts more strain on the belt...if the belt is not new and pulleys check out, (and tensioner is working properly) change the belt.

fan belt or drive belt loose or worn. If it has tensioner, try replacing belt, if it has an adjustment to tighten, Inspect belt and if o.k. just tighten it, but I suspect belt worn too.