134a converted 92 tercel question

[jomersexual]

there is a sticker on the under side of the hood on my 92 tercel that says it was converted to 134a in 98. I put 2 small cans of 134a in it with no gauges which made it put out fairly cold air but I think it could be better. Going to get my buddy with a 134a cylinder and gauges to recharge it if I can find out what the pressures should be?? I know very little about a/c in general

[96paseo]

Originally Posted by jomersexual

there is a sticker on the under side of the hood on my 92 tercel that says it was converted to 134a in 98. I put 2 small cans of 134a in it with no gauges which made it put out fairly cold air but I think it could be better. Going to get my buddy with a 134a cylinder and gauges to recharge it if I can find out what the pressures should be?? I know very little about a/c in general

Good ranges are 30-40 psi low side and 185-200 psi high side. Keep in mind that 134a doesn't cool as well as r-12. Your system may cooling as good as it possibly can. If your system gradually loses its cooling power, the compressor shaft seal and/or system o-rings are leaking the slowly letting out the charge. Was the compressor working before you added the 134a? I just replaced all o-rings and filter/drier on my camry yesterday. Will see if the charge holds for more than 3-5 days.

[WilliamRobert]

It should say on the sticker how many pounds of refrigerant and how many ounces of oil the A/C system takes. A/C systems require the exact amounts of each to run properly. Too much and it won't work right and can overheat the system, too little and it won't work right and you will not get enough cooling. Make sure that you use the correct oil as well, as R-12 and R-134a use different oils and are not compatible.

A/C is one of those things that if you don't know how to fix it, are better handled by a professional. They have the training and equipment. Plus the eco-nazis will be on your case if someone sees you letting the refrigerant out. I don't know how they are allowed to sell those little bottles at the parts stores.

was the a/c system working before you added the new stuff? If there is a leak, it should be fixed before you try to add some more. I agree with 96, checking out the compressor and o-rings is a good place to start. Might want to check out the condenser as well. I had a June Bug go through mine once. but a lot of the time, there is so much dirt, leaves and stuff in between the condenser and rad that there is not enough air movement to cool the system down. Does the fan in front of the condenser turn on as soon as you turn on the a/c? The evaporator fins like to plug up as well, it gets wet and then the dust sticks to to it and restricts the air movement. All easy and cheap things to check out. I like easy and cheap. lol.

BillyBob

[Todem 76]

Another thing is if you don't pull vacume before adding the refrigerant it will not get all that can go into the system. Need a machine for that.

[p5150]

I just rebuilt my 92 Paseo A/C system and converted it to r134.

every single o-ring replaced
cleaned and flushed all components
new receiver/dryer
new expansion valve
new compressor
reserviced with PAG/UV dye oil
r134 adaptors installed with loctite
serviced with r134 WITHOUT additives


System held vacuum for 12 hours so I serviced it. I put in approximately 20 ounces of r134. The servicing amount for r12 is listed at approx 25 ounces.

I have been gone for about a week so I plan on firing it up when I get home to see if it held. Im confident that it did.

[96paseo]

Originally Posted by p5150

I just rebuilt my 92 Paseo A/C system and converted it to r134.

every single o-ring replaced
cleaned and flushed all components
new receiver/dryer
new expansion valve
new compressor
reserviced with PAG/UV dye oil
r134 adaptors installed with loctite
serviced with r134 WITHOUT additives


System held vacuum for 12 hours so I serviced it. I put in approximately 20 ounces of r134. The servicing amount for r12 is listed at approx 25 ounces.

I have been gone for about a week so I plan on firing it up when I get home to see if it held. Im confident that it did.

A standing vacuum test is the best way. Keep in mind that you'll need more 134a to get the desired temp compared to R-12. The specific heat and system volume is the difference. R143a sucks compared to R-12. My camry is currently putting out 41.5 degree air on re-circ after replacing the o-rings and filter/drier. On outside air its about 47.5 degrees. I used R-414B as a drop in replacement. Its compatible with mineral oil and works almost the same as R-12. I couldn't be happier with the results.

[p5150]

All of the data that I have read requires a service charge of approx 20% less by weight when servicing r134 compared to r12.

Putting in any more r134 will overpressurize your system and blow your compressor seal

[96paseo]

Originally Posted by p5150

All of the data that I have read requires a service charge of approx 20% less by weight when servicing r134 compared to r12.

Putting in any more r134 will overpressurize your system and blow your compressor seal

True, its always good to follow the label. Car systems aren't defined as "critical charge" but overcharging will only hurt your performance or worse. My label was completely worn off so I just went by pressures once I got the system running with the first shot of gas.