hsiehd

I was recharge R134a to my A/C for 93 ES300.
The gauges read 40 psi ~ 45 psi at low pressure port (Compressor work that read 40 psi then go up to 45 psi after Compressor not work) at air circle inside of car mode.
The gauges read 43 psi ~ 48 psi at low pressure port (Compressor work that read 43 psi then go up to 48 psi after Compressor not work) at frash air from outside of car mode.

Can someone know which one is right for charge?

Thanks

David

GEORGE_JET

While the copressor is running, at a fast idle ( 1200 to 1500 rpm ) you should be running around those pressures. You may have a little too much of a charge. What is the temp of the air comming out of the vents?

hsiehd

I did not measure the the temp of the air comming out of the vents.
The above measure at idle 750 rpm, but I do not very sure because I did not check it since I charge the R134a.
Did someone know what is pressue range must be on low side?
Because the charge gauge show 25 psi ~ 45 psi need filled.

charley240

iTrader: (6)

did you convert it already to r134, isnt the stock r12?
goodluck
Charley

hsiehd

The A/C system was total flush and new receiver and expansion valve.
Compressor also from 03 car but using old Magnetic Clutch.
The oil is PAG and 2 A/C hoses also rebuild too.

GEORGE_JET

It is better to be a little on the low side, than pushing the high side. With the engine running around 1200 to 1500, ac set to max cool, with the cabin fan set to max speed, ambient temp around 70~75 deg. Add freon till you get around 38 to 40 psi. Then check the outlet temp. Keep in mind that the system was designed for R12, which runs at a considerably lower pressure than r134. With a condenser and evaporator that is pushing 15 years old it would be a good idea to stay on the conservative side and run at the lower pressure Besides, you did not mention changing out the pressure switch. If you give it a full charge of r134 I am willing to put money that you will trip the high pressure switch on the first hot day that comes around.
I have a 92 that was converted to r134, when I charged my system I charged to 38 psi on a 80 deg day. My car is dark green and with this charge I was getting 42 deg air from the vents all summer long, ( in Texas ). You can allways add a little more freon if you are not pleased with the results.

hsiehd

Thank advice, I will recheck it when first hot day that comes. I did not change pressure swith since Toyota R-12 AIR CONDITIONER SYSTEM RETROFIT guide did not show need change pressure swith.

GEORGE_JET

No problem, You do not really need to replace the pressure switch, but it is good to be aware that it is in there. It is a dual action switch which opens when the pressure is too high / low. If you charge the system using the gauges only, you could end up tripping the higher pressure switch and having the compressor cycle off. My ac does a good job, I think you will probably be happy with the results on your conversion.