R12 Topping Off

Yes, you're going to need gauges to do it properly. And unless you're a certified A/C tech, most likely you're not going to be able to get hold of any R-12..

R-12 is easy to get.

Get caught by a local EPA agent:

You'll say dick is easy to get in federal prison too!

Refinish King

Shop manual goes by condenser inlet temps vs. evap. outlet temps. If you put a gauge on the low side you'll see at what pressure the low side cutout comes on. I think it's about 25 lbs. (going on memory, my brother owns my '89 S Blazer now). Basically if you charge it enough so the low side cutoff doesn't kick in it will have enough in it to cool OK. With the motor revs up to 2-3k make sure the low side doesn't doesn't pull down enough to trip the low side cutoff. I usually go 10lbs over the cutout pressure with good results. It should be a warm day when doing it this way, at least over 75 F . That's how I quickie charge auto systems, 'specially the ones I have no specs for.

Try the forums at

People who know better than me are going to hate what I'm about to say, but if nothing else is wrong with the A/C you can get the R-12 charge about right if you monitor the inlet and outlet pipe temperatures of the evaporator while the engine runs at fast idle (must be fast, and run the engine at least 10 minutes before charging) and you slowly (emphasis on "slowly") put in R-12 until the outlet is almost as cold as the inlet. Ideally they should be equal, but it's safer to undercharge than overcharge.

Any car repair manual that covers GM vehicles since they went to orfice tubes?

...because it's got the GM R4 compressor that loses shaft seals on a regular basis.

R12 is available, but expensive, and top-up charges will not last. You will very quickly spend a lot more in R12 (to say nothing of tools and manuals to put it in properly) than to fix the problem correctly.

-Stern

||Get caught by a local EPA agent:

It would be a lot harder to find an EPA field enforcement agent, much less one that is interested in a DIY guy buying 3 cans of "contraband" from an individual. It's not even on their radar screen. I have never heard of any prosecution from this law, ever. Texas Parts Guy

Come to the Island:

Northumberland County Pennsylvania. Where they will prosecute you for wearing pants "Gangsta" style. (Not that I think that's a bad reason to prosecute for!)

But out here, They'll prosecute you for farting! Air pollution! Unless you're on the correct political parties registration list!

Refinish King

I thought I have heard recently that you can buy R12 almost anywhere is US?

"almost" anywhere?? No, you can buy it ANYWHERE in the US, as long as you have an EPA card. Any of the popular chain auto parts stores have it in stock, just show them your card! As for getting it without a card, I am sure that is possible to, but not legal. Greg

Are you EPA licensed?

Sure you can!

If not, no you can't!

Refinish King

Just out of curiosity, how much are you going to pay for a can of R12 ? Your gauges should read somewhere around 30 on the low, 250 on the high at high idle. This all depends on the temp outside and the condition of the compressor and the rest of the system. Feel the outlet (large) tube from the evap to see ifs it cold, it will be when its full (if everything is good). If for instance the expansion tube is plugged, you will probably blow up a high side line while trying to get it cold. If it doesnt start to cool after one can, be afraid :)Again, how much are you going to pay for a can of R12?

Around $20/can... I figure if it lasts the season then that aint too bad!

One more question! What is size of the can or container available to choose from and the price range? Thanks for your help!

Where the hell are you getting R-12 for $20/can? Dreamland?

Try ebay

$10 to $25/can is the going rate.

-Stern

That's dirt cheap.. why are so many people recommending everyone convert to R134a if R12 is that cheap. Sounds kinda silly to me.