Ok, so my car has a new motor in it (250 miles at the most. 305 to 350 swap) and when I bought it from my buddy he didn't fill the system with r12 after removing the compressor, so how would I properly fill my system? I'm going to be using autofrost, do I just fill the low pressure side or the high side too? And is there way to pressure test my system for leaks before I fill it (without taking it to a mechanic) I really need ac, I live in central Louisiana and it get extremely hot and humid here, also any tips on a website to find ac hoses and other parts would be greatly appreciated (not sure if anything would be different since the bigger motor swap) thanks again guys!

 

You need a vacuum pump, pull vacuum on it for 30min then see if it holds, if not you will need to put freon in plus dye, then look for the leak with a uv light.

Also make sure you have the correct oil in the system.

 

What psi vacuum should I pull, also is the oil in the freon or do I add it separate? It's all r12 stuff, so if it does have oil its the right kind

 

Also if it does have a little freon in it, how would I flush/evacuate the system?

 

You need to read the can, if it has oil in it then make sure you dont over fill the system, also note it is NOT r12 it is Autofrost.

Need to pull -30Hg so that it will evaporate the moisture in the system, when done let it sit for about 15-20min, if it holds the vacuum it should be fine.

 

With an evacuation machine otherwise you can just let it out the schader valve.

 

Ahhh ok, how many cans of autofrost will an empty system hold? (I believe I read 3 cans somewhere) and do I just fill the low pressure side and it blends with the high pressure somehow? Sorry for all the questions, just really wanting to do this the proper way and learn as much as I can

 

You fill from the drier, as far as filling you need to read the compressor lable or the manual to see how much oil and freon the your system takes, to much of to little of either or will hinder performance.

 

Thank you good sir! if I have anymore questions ill be back tomorrow evening after work

 

The low side is the suction side. The side that refrigerant will flow INTO the system.

The high side is the outgoing side. The side that stuff flows OUT OF the system.

If the car is turned off, it won't make any difference which side you fill it. (Pressures would be the same at either the low or the high side)......But if the engine is on, then you must use the low side only. Because if you use the high side with the engine on, it will send very high pressure to the Autofrost can and the can will explode in your face.

For safety's sake and not forgetting a step, I'd recommend putting refrigerant in using only the low side. The low side shraeder valve is on the accumulator (aka the big silver cylinder).........The high side is a thin line with a tiny cap on it. Make sure to wear some safety goggles too.

The A/C system will be the same, regardless of it being a 305 or 350. All parts are the same. Same location.

 

You really should have a pressure gauge to see how much you have in it. Buy a can of R12 conditioning,oil,fill,with the dye in it, has everything you need in on can. Then you might need 1 or two more cans of R12. I just did mine and it is like ice!