After 18 years of cold air my AC is not cooling too well this spring. I have some R12 and a fill hose but am not sure where the fittings are. I found my sight glass and there is one valve just above the compressor, but the second valve is elusive. Where is it and which one is the low pressure valve? I plan to add a can and see how long it stays in before trying to find the leak. Thanks!

 

the one on the compressor is the low side and the one by the radiator is the hi side. you would want to put it in the low side. You should turn on the car and put the a/c on max cold on hi so it creates a vacuum

 

Will ac shops fill up our ac systems?

 

I called a couple shops locally and was surprised that they no longer had any R12, even recycled. They were all purging it from systems and reusing it for a while. I guess the demand is pretty low now fo R12. They both wanted to convert me to R134, which I want to avoid as long as possible.

 

I do know that Express Oil Change still has R-12, well at least here anyway. Try them or you may have to get a retrofit to R-134A. Sorry about the news.

 

Well, I still have a few cans of R12, and several sellers had some on ebay. This car has a sight glass, which really aids in topping up a system without gauges. It's remarkable that mine has only just now got low enough to affect cooling. I'm not going to keep on putting freon in if it doesn't hold for at least a few months, though. I'll get some help in finding and repairing the leak, but keep R12 in if I can.

 

Can anyone post a picture of the low pressure valve on the A/C compressor on a 92 SC400. I need to add some R12a and want to make sure I've got the right valve
thanks

 

I don't have a pic, but the fitting you are seeking is right on top of the ac compressor, facing directly forward. Make sure this valve is not leaking. This was the source of my leak last year. I just tightened mine a bit and it stopped. I have not had to add any freon this year. The valve is the same as a schrader tire valve and the same tool will work on it.

 

My tool has dual ends-small on one end and larger on the other. I can't remember which fit the Lexus. There are two sizes of valves. I bought a small kit with both size valves and the dual tool. Just watch the sight glass till it is clear when putting in the R12. I found plenty of freon on ebay, but it is pricey. I paid around $20 per can, maybe less since I bought a case. Good luck!

 

Low pressure valve is on the pass side rightby the abs unit just look at the line that goes in to the fire wall.

 

Sorry I'm still a little confused and just need clarification- as I understand it the valve on the 92 is on the compressor? And unless I'm mistaken its located on the drivers side or is it on the passenger side by the fire wall?. Last question u mentioned the sight glass?? Thanks in advance

 

Well, mine is indeed on the compressor. My car is a 92 SC400. I would not have been able to add freon there if it was high pressure.

 

Oops mine is a 97 so I just skimmed through and failed to pay attention to the year.

 

My 92 has the low side valve by the ABS stuff as well, but I have an SC300. It sucks trying to put a hose on there without burning your arm all to hell on the twins.

 

While we are at it...since these old cars used the now defunct r12, can I just do a recharge with the new stuff?