Here is a dumb question: Just how do you flush an AC system?
For the life of me, I dont know how to do it. Does anyone know where I can find a detailed procedure with diagrams showing me what to do?
Thank you very much, winter is coming. Could someone show this to Larry Bible?


Dumb question: Just how do you flush an AC system? (83 240D)

IS THIS A TRICK QUESTION ?
Have you considered getting and reading the FACTORY SHOP MANUAL on Air conditioning for your car ?

IS THIS A TRICK ANSWER ?
Have you considered doing a search on this site and reading the threads ?

you can use a Flush gun and flush capturing unit, or you can buy a premade pressurized can of Flush with an attachment, or if one is clever they make a compressed air method to inject the flush into the system... I am looking for the cheapest, most economical method...

Yes, you can do either... the pro units recycle,clean and dry the fluid and use it again...
The unit you are more likely to use is a one way deal.... put the liquid flush into the container which exits it from the bottom... and is powered by your air compressor . My impression is that this nice specialized tool costs about $45 from people like Carlisle, ACkits... etc...
EVen if you use this one way deal... the descriptions of serious guys usually meant catching it on the other end... and reusing it... then putting clean into the unit and flushing a final time... many also suggest flusing both directions...
Another way is to use one of this new Bottom Tapping contraptions.. ( I just got one for R12 and one for 134a from my JohnDeere dealer ).... this is described by several people to use some things like berryman chemical cleaner, WD40,mineral spirits, etc... but I think that the legit flush is safer in terms of not leaving bad residue...
You do not want to flush the compressor, the Txvalve, the dryer, and some say not to flush the evaporator.. however, the FSM says to use the old Txvalve and take out some of the insides... and make a fitting for the flush unit... so you can flush it and the hose going forward.. then close up those areas...
The pros also use DRY nitrogen available from welding supply places to finally blow through the system after the liquid flush has been used... be sure to ask for DRY nitrogen if you decide to do it this way...
On the ' CHEAPEST WAY" ... the cheapest way in the long run may not be the cheapest way during the initial operation.. if your new items are messed up by not flushing well.. then you will have problems years before you should .
You should go and read all you can on aircondition.com and the forums there... all sorts of questions and answers ...
Then call Trey at Carlisle in San Antonio... they specialize in this stuff... and they are friendly experts... they have talked me out of a couple of things... they have not just tried to sell me everything I asked for... I like that kind of deal...
The " bottom of can tapping" deals ($10) each... allow you to just use something like the wd40 with its pressure to run Liquid through a line to flush... since you are taking it from the bottom of the can... this is descibed somewhere...

flush gun picture....

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