So I picked up a free Frigidaire stainless side by side and A comparable fridge to the one I have would cost about $1200. Its funny because when I got the fridge the guy said he payed someone to come look at and the tech person told him that the compressor was out and that it would cost $600 to fix, So the guy decided to give the fridge away. So I decided I would try to fix it, So I ordered a compressor kit off ******** for the fridge which cost $80. The kit came with some electrical pieces that go on the back of the compressor, so I put these on the old compressor and after that I plugged the fridge in and the compressor turned on, before when I fist got it, it would not turn on. So I let it sit over night but it did not get cold at all! So I called around and someone said even if the compressor is running it still could be bad, But Im wondering if there is a leak in the system? But if I do fix the refrigeration I would the the tech person would have a way of checking the pressure of the system to make sure there is no leaks? So what do you think?
Thanks

If the compressor is vibrating and getting warm, but not cooling, the system is very low on refrigerant.
Generally, you cannot just change compressor parts without verifying they will not damage the compressor!
If the compressor now is not vibrating, you probably blew out the start winding.
Seem like your original problem was a refrigerant leak which usually damages the compressor.

Ignore Letsride, he is confusing the issue, check to see if the compressor is vibrating and warm,post results

ok, I read a few things, and someone missed something.

Yes, if the compressor is vibrating and warm, it probably has damage. but I know a way to check and see if a compressor is working using just a clamp multimeter.

first, you take the cord, and locate the side with the ribs on the insulation (usually left side of the cord). take a razor blade or box cutter and cut away the ribbed part, MAKE SURE YOU ARE CAREFUL AND DO IT WITH THE FRIDGE UNPLUGGED!!! Also, make sure you do not cut away any insulation on the wire.

Take your clamp meter, and put it on 20 amp setting, making sure to put the wire inside the clamp of the multimeter. plug it up, and look at what amps you run. usually its around 1.8-2.6 amps, but it will tell you on the compressor what amps it should run. also, the defrost heater will run an extra amp.

if your amp reading is too high, then your compressor is bad.

when i did appliance repairs and service work, a lot of the GE brands came in with holes in different parts of the cooling system (causing freon loss and compressor failure). IDK why it was GE brands (GE, frigidaire, etc.) but it always was.

also have you checked the defrost board (usually located in the top of the refrig side, you have to take the whole thermostat control down, look for a box the size of a pack of cigarettes with a bunch of wires and a connector hooked up to it.) if there are burn marks on the board, then it is bad, and not cheap to replace.