I wish I had asked this beforehand. I probably would not have added the 2nd can of R12.

I hope I didn't overcharge the system. (How would I be able to tell?)

Measure pressures w/ an ac manifold gauge set. High side should be about 2.5*ambient air temp entering condensor. Low side should be 25-30 psi just before compressor cycles off.

good luck

I wasn't able to hook up to the high side unfortunately. Looks like this is the adapter I need:

https://www.ackits.com/pc/90358/char...e+Port+Adapter

But I do know that the compressor was consistently cycling off at just about exactly at 25-30 psi. So maybe I am ok?

It may not be overcharged. If you get rapid compressor recycling on hot days, it may be overcharged (HP cut-out protecting compressor).

Yes, you need that adapter to connect gauge set.

good luck

Just ordered one.

Do you know what pressure the HP cut-out switch opens at?

It cuts out at 455 psi for high pressure and 28 psi for low pressure.

So you added 24 more ounces of R12 to a system that was cooling pretty well? The sticker on your car should tell you the total amount of R12 needed in your car.

Please don't ever charge your system blind again, because this is dangerous. You need both the high and low side pressures and the temperature at the vents and the outside temperature and humidity to diagnose any problems with the a/c system.

I would avoid using the a/c as much as possible until you can test the pressures.

I'll be able to check the high side pressure as soon as my adapter arrives.

Is this chart I found (below) at ACKits.com a good guide?

http://www.ackits.com/aacf/ptchart.cfm

A pdf of the 91 accord goes through how to evaluate the pressure/temperature with R12.

Go to the common diy thread on top of the gen tech help forum and open the online manuals link. Then the honda tech link will get you to the 91 manual. Page 15-66 has the temp/pressure graph and the conditions to test.

You know I downloaded and unzipped that manual a while back. I find it really difficult to use the way it was done.

Or maybe it just unzipped in a strange way for me. None of the files are labelled or indexed etc. Just page numbers. I was thinking maybe this is due to copyright concerns.

In any case I have the page up (thank you) and I'll use it.

I had a chance today to check the operating pressures.

The high-side service port adapter fit just fine. But I ran into an unexpected snafu with my high-side gauge. It is reading around 350psi when it's disconnected.

I have no idea why. It does increase from that point upward when connected. Is there a zero-adjustment for a gauge like this? It is a "Uniweld". There is a screw on the face of the gauge:

Attachment 17484