The ac in my mini was removed when I got it.
But was still with the car, seems to all be there.
When fitting it back in, can I just use some of the auto parts stores refills? Or would I have to have a shop re charge it.
Also the high speed fan is always on. Could that be because of the AC system being removed? With it being unplugged just throwing it into a constant high speed fan mode?

 

You need to take it to a certified shop that has the equipment necessary to introduce not just the correct amount of refrigerant but also the PAG oil.

 

Sounds good.

 

You would need a vacuum pump, gauges, refrigerant, and a scale to weigh the correct amount of refrigerant. You need to replace the drier since it sounds like the system has been open for some time. Replace all the O rings on the connections. If the compressor is bad you will need to flush the lines in case any metal hot in the system that includes the condenser. The shop will pull a vacuum to see if the system has leaks before charging the system. If it doesn’t hold vacuum you will have choice on what to do to find the leaks. Most likely they will charge the system in order to find the leak as it is impossible to determine with an empty system. They will put dye in the system to find where the leak is and use a sensing device that can sniff out refrigerant. Good luck.

 

I don't think the compressor is bad. I think it was removed more for (let's try to take weight off cause I think it's gonna be faster) reasons.
The pulley, as if it wasn't engaged spins freely with a touch of noise.
Spinning it as if the AC was on and engaged, theres some resistance which seems as it should.

 

You need to spin the center of the clutch, the piece that is engaged when the electromagnetic clutch pulls it to the pulley. That will show you if the compressor is locked up. Also, replace all of the O rings ( I usually use complete kits from Rock Auto when I do a car. I don't know if they have one for MINI though because I haven't had to do one yet), as well as the expansion valve and orifice tube (if it has one) when you do the reassembly. The compressor oil does need to be done, but you can do that yourself. Research which oil it takes and buy an appropriate amount (like car engines, not all compressors take the same viscosity!). Then empty the compressor with it out of the vehicle by tipping it upside down or on it's side (whatever works) Then you can refill the compressor with the new oil by just pouring it in. I forget which port you use, but I want to say the low side, just because that is where the oil charge would be put if it was put in with the manifold and gauges. The low side would be the larger of the two ports because the high side is transporting compressed gas and a larger pipe would let it come out of compression. I would also replace the high and low side schrader valves while you are in there since the seals dry out over time. The final while you're in there is to replace ALL of the foam seals in the ducting. over time, they dry out and turn crunchy, losing their seal. When this happens, you end up doing a great job cooling the back side of the dash but not so great cooling the cabin. When I built the A/C system in my 1991 Geo Metro, the output at the vents doubled it's air speed after resealing the ducts ( I measured it with a hand held anemometer I kept with me while delivering pizza. I also kept a geiger counter with me just for fun...). I would also consider replacing the electromagnet for the compressor clutch. You can buy them on eBay. I think I paid $28 shipped to my door. I didn't use it yet, but the wire to the original clutch was completely devoid of insulation and I wound up repairing it with liquid electrical tape instead.

One more thing: DO NOT OVERCHARGE AN A/C SYSTEM! It will make it cool less, not more. The reason is that the refrigerant needs to phase change from liquid to gas and excessive refrigerant can't complete the cycle. It will kill the expansion valve and can also kill the compressor by making it try to compress a fluid. Fun Facts: A/C systems work off of Bernoulli's principle and are also a reverse steam engine (Rankine Cycle).