juanito935

i know this thread exists already but here goes again. i have a 1992 ls400 trying to do the a/c conversion but not sure what needs to be done and where they are. if anyone has the service manual i can use i would appreciate it. thanks for any help.

LScowboyLS

to do it right:

new compressor internal seals, i.e. new compressor
new condenser (mandatory if you want it cooling in Nevada heat)
flush system (mandatory)
new expansion valve (can possibly just be adjusted)
new refrigerant, (mandatory)
new compressor oil (mandatory)
evacuate & recharge

this is really not a good plan unless you have several $1000 to burn or a lot of free time!

what's wrong with R-12, it is available and works better than 134a! (hence the need for the new high efficiency condenser mentioned above)

timmy0tool

iTrader: (7)

where do we get R12?! around here it's scarce!

LScowboyLS

it's around to anyone reputable, harder for a DIYer to acquire, but truly A/C is really not something the casual wrench turner should be messing with other than a little top off of the refrigerant, it is a whole world of its own, much like auto tranny repair or ECU repair, etc.

johnnyg66

I went with freeze12 over 3 years ago cost about 115 to switch. It works great. I probably need to have it serviced this summer.

dengman

a reputable shop might have an R12 machine. Alot of smaller shops expect you to switch to R134.
R12 is way coolder that R134.

But as LScowboy said alot of things should be changed to do it properly.

Kennyr44

Just evacuate the r12 out. Change the fill valve to the r134 fitting. Now suck down the system with a pump and fill with ester oil and 3 cans of r134. Mine has lasted 10 years this way and it blows ice cold. All the other more elaborate methods are a total waste of time and money. By the way I have been a mechanic for 30 years. I was there when the ban started. I worked for Volvo. At first they told us to replace all o rings etc. After six months they sent us a service bulletin saying to do what I just explained, it worked fine. Also many of these older cars with the original radiators wont cool because the airflow is restricted through the condenser. The fins are so plugged up its worth replacing for ac and engine cooling. And by the way the R134 cools just as cold as r12.

LScowboyLS

maybe on an old $2000 beater LS400, but not on mine!!

usually the only thing that leaks on the world's most reliable A/C system (thanks, NipponDenso!) is just normal hose permeation (so typically there is essentially no true leak to be fixed), why not just take it to a reputable A/C shop and have them top it up with a few ounces of R-12, which is what the car was designed for! (and perhaps an ounce of oil) or whatever small amount of refrigerant it needs, - I can't believe that this would cost over $100 and I used to own the largest auto A/C shop in Arizona, I am failing to see the problem here that requires all of these non-standard solutions!


now this part I strongly agree with!!

dengman

R12 gets to a colder state faster. Which is why the condenser is smaller, compressor is smaller, and the system runs at a different pressure than R134. Sounds like R12 is more efficient than R134.

Retrofit rigging doesn't work on all cars. Do it right the first time. Change the necessary components to have optimal efficiency vs rigging that might work. Might work tends to lead to more time spent.

120 outside temps with a retrofit rig running r134 vs R12... I am CERTAIN the vent temps of R12 will be colder than r134.

Kansas

I couldn't tell any difference after I had a 90 LS professionally converted to R134 in around 2000. After the conversion, I remember four of us sitting in the car in a sports stadium parking lot on a 100+ degree day for over an hour with the A/C on. We were cool and comfy. I drove the 90 LS for another 3 years after the conversion with no problems. I don't remember the exact cost but I think the conversion back then was around $500.

johnnyg66

Well I checked around a lot before I went freeze 12. No one I called had or would bother to get it anymore. Cost per pound was getting to high. Heard yesterday its getting up to 60 dollars per pound. Some shops said to call a home heating/air company. So far this stuff has cooled as good as r12.

Kennyr44

Heres the problem. Anybody you ask and anywhere you go they will have a different answer to what should be done for the retrofit. Some people say you must change all the o rings, etc. All this will just pad the bill. R134 is the least expensive option and the correct option for the environment and it works and lasts with just a swap out. Ive done it to several cars that I serviced for long periods of time and never had one with any problems many years later. You may have to add a can every few years like any system with rubber hoses but its only $10 and available everywhere. When the r12 was banned everyone was freaking out over nothing. Using expensive r12 if u can find it is a bad choice. The freeze stuff peaks my interest but still isnt my preference.