Can Freon be siphoned?

[rs4pro3]

Can Freon be Siphoned from one car to another? The R12 in my 85 325e needs topped off, now my non running 1981 633csi still has R12 in the system, could I some how siphone the freon from the 6 to the 3? I would just drive the 6 down to a local mechanic and have the system evacuated but can't in it's current state. I wonder if they can travel with the equipment? I don't have the cash to top off the R12, and would convert but don't want to waste the R12 in there.

[RobertK]

I would assume you could possibly create a custom pressurized hose with a valve / pressure gauge in the middle you could hook up to the purge valve of one car and the fill valve on the other and then open the valve to the it flow over.

This is just a suggestion.. never tried this before but it's not a bad idea if you're trying to scavenge up some R12.

[rs4pro3]

I already have a pressure manifold set, I'm just wondering which way would the freon go? as I don't want it running back threw the system to the 6. I don't think I need much, as it has 20psi on the low side instead of the 30 it should.

[AdamF 88iS]

How are you planning to do this? What equipment do you have?
You really need a vaccum to do AC right. After you suck it out you can then pressurize it into a container.

Only hook up one side of the system to the vaccum pump, you want the system to hold vaccum. The neg pressure lowers the boiling point of water to help get all the moisture out, and also puts the R12 into a gas state so it evacs more easily.

[AndrewBird]

If you just hooked one car to the other, wouldn't the two cars just equalize in pressure? So the lower car would gain some, but more then likely not even enough to worry about.

[screamingbmwe30]

no, the pressures would just eaqalize. you have to recover it from one system and then feed it back into the system you wish to charge

[rs4pro3]

Ok thanks, I believe the headgasket on our 86 528e has blown again, I'll run a compresion check to see for sure. If it has then I'll just drive it to the shop and have the R12 evacuated. Or call and see if they can bring the equipment.(which I don't have). I have a manifold set and access to a vacume pump but that is it.

[e30evolution]

if both cars run and the compressors work then you could put a hose from the high pressure side on the 6 to the low pressure side on the 3.... there would be no way of measuring how much you put in. but i would work

[rs4pro3]

If the 6 ran I would just drive it down to the closest AC shop and have them evacuate and salvage the R12.

[808BMW]

The equipment isnt that big, we just changed the expansion valve today and my mechanic vacuumed out the system at his house.

[AndrewBird]

no, the pressures would just eaqalize.

That's what I said.

[e30evolution]

no, the pressures would just eaqalize.

That's what I said.

if you have both the compressors running you will basically be pushing the refridgerant from the 6 series high pressure side and sucking the refridgerant from the 3 series low pressure side

[AdamF 88iS]

no, the pressures would just eaqalize.

That's what I said.

if you have both the compressors running you will basically be pushing the refridgerant from the 6 series high pressure side and sucking the refridgerant from the 3 series low pressure side

You would still need to vacuum the 3 first. Where is the air in there gonna go once you start dumping more freon in?