Flushing a/c system
 

When flushing an a/c system do you flush only the condenser or both the condenser and the evaporator.

Also, I want to use the compressor from my totalled '86 300E in which the A?C was working perfectly in an '86 300E that I just acquired. The old car had R134A but the new one is an R12 system.

How do I flush the compressor to use it with R-12?

I know of no proper DIY 'flush'. A proper Ester Oil flush requires specialised equipment to be performed correctly... nitrogen or chemically dried air. If you can all components are to be flushed.
Flushing with anything else, including refrigerant is unproductive.
More normally you simply drain the oil then pull a vacuum on the entire AC system for 30 minutes then let it sit under vacuum (hold) for a further 30. Done.

You can run the 134a compressor with 12 or 12a no problem. Where do you get 12?

Drain the oil from the replacement compressor. Install it. Pull the vacuum as above... if it maintains vacuum through the 'hold' part recharge with refrigerant and away you go. If it drops below 27 inches of mercury (27" Hg) find the leak before charging.

1."Flush" both Condenser and Evaporator.
 

2."Hand" Turn the Compressor whilst flushing the "Old" Lubricant with the "New".
DO NOT Purge/Flush the Compressor with Chemical "Flush" !!!
Use ONLY the New Oil to Flush out the Old.

Any recommended flush and flush systems.

Thanks.

If you remove the compressor, you can flush the lines with compressed air and acetone. It worked great for my 300e.

Simply attach a rubber hose, add acetone, and push it through with compressed air. Be careful not to get any on the paint!


As far as flushing the compressor, I have no idea.

I've flushed many systems before using shop air. I use mineral spirits, then finish with lacquer thinner or alcohol. Before flushing, I disconnect the system at every junction and flush every component except for the expansion valve, drier, and compressor. As compress ignite said, the compressor is flushed by pouring in the proper refrigerant lubricant and working it through by hand rotating the compressor.

Bookmarking this thread - summer is coming! Need to get a new condenser for my SD, clean everything out and hope for the best. For the record, Harbor Freight has AC vacuum pumps with both R-134 and R-12 attachments for about $30, with a decent gauge it should be a cheap way to find leaks...

I am a ticketed Refrigeration Engineer.
Understand that alcohol, lacquer thinner, acetone, and other solvents are detrimental to the components in the system and are incompatible with the refrigerant itself. Even the air you are using to evacuate the solvent is contaminated! Off the shelf solvents should never be used in an R12 or R134a system! There is a product available but the layman should not be flushing an AC system unless you have the proper tools as you are simply contaminating the entire system! It is like washing your car with dirty Varsol (parts cleaner)... it gets the dust off but is it a good idea?
For the layman who feels he must flush the system use the specified mineral oil only and evacuate with filtered and chemically dried air or nitrogen.
Anything else is worse than leaving anything you feel you need to flush out in there.
Flammability of solvents is NOT a concern as the refrigerants themselves are typically flammable.

Professional A.C. Flush products
 

Excellent system. Have you tried purchasing it outside of a speciality retailer?

That Ain't Happening.They've a "Distributor Network"
 

Atlanta,GA is the closest.
'Got to imagine it's very similar to the Wurth circus.

I obtained some Frigi-Quiet from one of the Local Shops.
It works SO well,I have to keep myself from looking for excuses to use it!

Very good information because this is exactly what the layman needs to do a proper job rather than risk contamination with all kinds of solvents and dirty purges.
How much... it may be cost prohibitive for the shadetree?

Thank you all for the info and tips. Will report back after I am done with the flush.