'93 Convert A/C from R-12 to R-134a

[geojim]

My '93 is low on R-12 refrigerant to the point that the compressor clutch will not engage. (Verified this by by-passing the dual pressure switch for a second). The R-12 obviously leaked out so I think the first step will be to have the shop draw down the system and run a leak check to find where the leak happened. My question is for the next step.

Has anyone simply converted from R-12 to R-134a by using one of these "complete" kits I have seen at AutoZone and Napa for about $35.00(US)? There are no gaskets, seals or compressor parts in this kit. Anyone used one of these kits to convert their Metro to R-134a? How will the R-12 compressor do with one of these kits? Also, is it worth changing the dryer/drier at the same time?

Thanks,
Jim

[geozukigti]

I bought one of those kits last summer for my blue vert. I had the system discharged, let the new PAG non-coagulant oil in, charged the system up to pressure, and it blew ice cold air for about 5 minutes, and the compressor locked up. Locked up so hard, that my engine stalled. So no, i personally wouldn't recemmond it.

[geojim]

OK, thanks - doesn't sound good. Compressor designed for R-12 could not handle the R-134a? So if you want to convert you have to buy a R-134a compressor?

I'm taking the Geo into the shop next week for a couple of other items and I'll ask the mechanic. If it turns out that the A/C leak is in a major component, the question of R-13a may not be important right now anyway. Jim

[geojim]

Went to my "shade tree" mechanic today and we, mostly he, did several things to the Metro. He did convert it to R-134a and changed the dryer, and the cold air appears to be holding. Several scary moments; about five minutes into it, the compressor started to go into cardiac arrest. He quickly removed some of the R-134a and it settled down. After another 5 minutes it did the same thing, he again removed some R-134a. The apparent overcharge was killing the compressor. Things appear OK right now, but time will tell. Jim

[Valero]

A couple of years back I converted my 92 metro using the convertion kit. It was easy, it took me 15 minutes, and yes you should not use the whole amount of new refrigerant and YES it works perfect even now.

[geozukigti]

I just gave one of those R-12 to 134a conversion kits another chance the other day on my 90' Lincoln. It had "non-coagualant r-12 compatible oil" in it. So far, so good. It's been blowing cold air for 4 days now. Maybe I just had ill-faith from a bad experience? lol.

[geojim]

Can the little single gauge that comes with the kit be used to determine the right amount of R-134a refrigerant for the system? I left it in the 30 psi range after releasing some as the compressor was locking up or recycling too much.

[geozukigti]

yes, that's what the gauge is for, is to determine the correct fill amount. You'll have to disconnect the gauge from the 134a bottle to get an accurate reading tho. Only take a reading after the a/c has been running got about 30 seconds (operating pressure and temp) to get an accurate reading.

[geojim]

When all else fails, I should read the instructions. There was a table with the kit that lists the range of low side psi readings that are appropriate for a specific ambient temperature.

[insomica]

"read the instructions"

Who ever does that? LoL

[geozukigti]

I didn't at first, and sat there for 5 minutes waiting for the system to suck in the 134a. Then it was doign nothing. Read the book, and whoops! Supposed to turn the can upside down . Worked great after that.

[geojim]

So far the little Geo is cooling pretty nice. I got a small temperature gauge to measure the vent temperature from AutoZone. The vent temperature, after a few minutes of A/C running, is 40 F. Feels gooooood...