Help! AC Dryer/Accumulator VIR. What to do? 74 SB.

[retired ralph]

I removed the accum/dryer.(It wasn't easy). I hate to spend the money on a new one. Can I take it apart and clean it? There is oil coming out of it. I see a "Factory air desiccent bag kit" at Advance auto. What is that? Thanks Ralph

 

[lars]

There are 2 failure modes of the Receiver/Drier:

1. The desiccant bag that the freon flows through acts as a filter, and the bag can get plugged enough to cause a restriction through the receiver/drier. When this happens, the receiver/drier acts like an expansion valve, and system efficiency is lost. You can easily test for this condition by simply touching the receiver/drier inlet and outlet lines when the system is operating: If one is hot and one is cold, the drier is plugged. If both are the same temperature, the drier is good. If you have pressure ports in the system on both sides of the receiver/drier, you can test for pressure drop to see if the receiver/drier is good.

2. The desiccant can be moisture saturated. Moisture in the system can cause significant corrosion and system reliability issues. There is no good way to test for this, other than that a moisture-saturated desiccant bag will also often be a plugged or restricted bag with the symptoms described above. Moisture in the system is caused by the system remaining uncapped for periods of time or by improper system evacuation during servicing. The receiver/drier and its desiccant can sometimes be "dried out" with an extended evacuation followed by a freon purge and re-evacuation. I've also seen people do a bake-out of the receiver/drier at elevated temperature following by vacuum evacuation. If the receiver/drier is suspect, we always recommended that it be replaced, since the time spent trying to rejuvenate it did not offset the cost of a new one. I've never seen a "rebuildable" receiver/drier, but if you can get it apart and replace the desiccant there is no reason it would not work.

Lars

 

[paz72vette]

I agree with Lars,

Use dry nitrogen instead of frean.

Time vs money. Buy a new part, old ones take time to fix/repair. Keep old part if numbers matching.

Good luck

Vito

 

[lars]

That's correct: Dry nitrogen works great, too, and it's less expensive than freon. Problem is, most people don't have access to a K-Bottle of nitrogen in their garage, but they do have a little extra freon if they're servicing the AC unit. If you have a bottle of N2, use a little of it for purge. If not, give the evacuated system a short burst of freon (which is also dry), and then re-evacuate. This will positively eliminate moisture from the system.

Lars