Freon overcharge?

[cam76034]

Added a can of R12 to my 90 Corolla, which would cool, but just not enough. Now it seems like it is even less cooler than before. Didn't use gauges, but can get some. How do I check to see if there is too much freon, and do I just bleed it off or what?

[tashirosgt]

You actually got a can of R12 as opposed to R134a? I don't think you can tell much without the gauges. Don't know about R12, but with the typical gauge set you need an adapter to use R134a from a can. The gauge hoses are designed to work with the propane-tank-sized containers. As to bleeding it off, that is a good question. I think the cans contains both refrigerant and oil. It's probably illegal to bleed off the refrigerant R12 directly into the atmosphere. And, with R134a, how can one get the oil level correct by bleeding?

[cam76034]

yes, real freon

[REN69]

get your flame suit on dude.. I smell a flamewar coming soon.

[toyomoho]

Overcharging can cause insufficient cooling, or it could be something besides low Freon. I thought I saw a gage setup for cans, check eBay or auto store. Perhaps the empty Freon can states if it contains lubricant. Some of these A/C systems have site glasses around the dryer. You can see if the system has bubbles (low), etc.

[retiredat44]

ask over there:

http://www.acsource.net/acforum/

[corolla1990]

1.65lb of r12 is what's needed to fill it up.

I recommend removing all old freon (and air) and then adding the r12.

r12 is tough stuff to get nowadays. I would recommend taking it to a qualified a/c technician so it doesn't get all wasted.

[Doctor J]

To check for overcharge:

1. run A/C on high speed for 2 minutes,
2. idle engine with A/C on for one minute more
3. while loking on the sight glass, switch A/C off

If you see the foam and bubbles for about 10 seconds after shut-off, the system is charged properly, if glass clears right away, the system is overcharged. Also, the overcharged system cycles frequently from on to off.