AC Condensor Flush - How To?

[PWagon]

I feel like I have over extended my requests for help from you guys, but I have a sh!t ton of projects to wrap up on my K5 in the next week. Anyhow, I need to flush out my condenser coil of all its oils and refrigerant. It's just fluids (no metal). I'm going back to R12 because I'm apparently old school and can't deal with 134 anymore (please don't try to convert me to 134). I found a place up the street from me and he can still get R12, and it's really not that much more expensive. Anyhow, what is the preferred / recommended way to flush out auto AC lines? I'd assume something like brake fluid and then follow up with pure alcohol (no water). Thoughts?

 

[Fordum]

No brake fluid. Don't use that stuff for anything except brakes.

Not sure what to use these days. There used to be a Freon type flush liquid but its probably been banned these days.

Most auto parts houses have flush solvents.
But, if the system is in good shape and has not had a failure of the dryer or compressor, I doubt that you need to flush it.

As far as I know, the PAG oil used for 134A is fully compatible with R12.

Back when the conversions were first taking hold, it was assumed that you had to get all the old mineral oil out and replace it with PAG.

But, after lots of folks just got as much of the mineral oil out and added the PAG with no problems, they quit worrying about it so much.

 

[British Slave]

Go to your auto parts house and get the commercial flush. Instructions are included.

 

[Fordum]

An update:

The older single ended PAGs were not compatible with R12, most of the newer double ended ones are.
So, without knowing which they put in your system, I can't say for sure if its safe with R12.

Don't forget that the oil lurks in other places than the condenser. There is quite a bit in the compressor, evaporator and the drier.

 

[PWagon]

My system has the compatible PAG (compatible with both 12 and 134). I know this for sure as it was completely rebuilt about 3 years ago. I was under the assumption the 134 and R12 could not mix? Is this not the case?

 

[Fordum]

Actually 12 and 134A will mix, and they actually sell refrigerants made of the mix. But, don't forget that there is not going to be much of either in the system after the pressure goes to zero.
Plus, you always need to pull a vacuum on the system to get any moisture or other things out before recharging, and that will get enough of either out as to not matter.

 

[PWagon]

Learn something everyday...

 

[Big Ray]

there's several good vids on flushing your a/c on youtube...I don't have time to link them right now.

Some parts can't be flushed, like the accumulator, compressor, and orifice tube.

for best results doing it yourself I would do the evaporator, condenser, and hoses individually.

think about going with a parallel flow condenser for the 134a before swapping back...works much better.