jdw1

i replaced the drier, evaporator, expansion valve, and compressor. no leaks anywhere to my knowledge. charged it with 2 cans of freeze 12 put the right amount of oil in the system, evacutated it for about 2 hours, all the pressures were in range. drove it around and it got pretty cold but not as cold as is should. then parked it and went to town a couple of hours later, and it took forever for it to get somewhat cool but it's not blowing as cold as it was. im getting really tired of jacking with it. any ideas what it could be?

abecedarian

yeah... there's a problem.
can't say much about what it is though without a manifold attached to the system to show the high and low side pressures.

and if you went through the problems of replacing nearly everything, why go freeze12? should've gone full 134a

jdw1

i put a thermometer in the vent and got a reading of 50 degrees and thats in the evening time and about 2500rpm. i heard freeze 12 should get down to about 32 degrees. my friend has freeze 12 in his toyota truck and it gets ice cold.

jdw1

heard alot stories of people coverting over to 134 in their toyota pickup and not happy with it. heard it could be due to smaller condesors and evaporators. due you know what the high and low side pressures should be? can someone post a reference chart of the pressures?

abecedarian

vent discharge temps should never get down to 32. if that's the case, the evap is below 32F and any condensation will freeze on the evap. also, if that is happening, the system charge is not correct causing undue stress on the system, particularly the compressor.
there are three or four different condensors used depending on year, make and model and some are interchangeable.

jdw1

what should the vent discharge temp be? high and low pressure ratings?

jdw1

anybody got the pressure ratings?

ssupercoolss

charged it with 2 cans of freeze 12 put the right amount of oil in the system, evacutated it for about 2 hours, all the pressures were in range

did you really do it in this order? if you did, it shouldnt be working. dont count on a converted sysytem doing better than 50 degrees at an idle, not moving. my 93 blows at about 39 with r134a. (going down the road) i honestly dont know why people fool around with the blends. (mention them at most a/c shops and they wont work on your stuff) depending on the ambient temp, your high side should be around 250. the hotter it is outside the higher that number will be.

PCE91V64x4

Hopefully you evacuated it an then put in the freeze 12.

How much difference is there between the outside air and the A/C air? Should be at least 20 degrees on a hot day (85-100 outside, 65-80 on the inside) if your A/C is working ok.

My A/C was converted to R134 before I bought it so I have no idea what the PO did to do the conversion. I have evacuated it and recharged it and added some oil from Advance that says it is compatible with both R134 and R12 and my A/C is freezing cold, so my AC system seems to be in good shape.

bwhyit

X2 on the 20 degree temp drop from ambient. That pretty much standard on all AC systems. You put 2 cans in but what is the charge amount specified for the vehicle? Overcharging the system is as bad as undercharging. You may have put too much in the system.

InternetRoadkill

How did you get yours to blow 39 w/ 134A? I converted mine and I'm lucky to get it to blow 50. What did you change and what are your pressures?

shortwing

I have been reading everything I can find and this is what I came up with.

The system capacity on my 87 4 runner is 1.3 - 1.7 lb. of cfc 12.

That works out to 1 1/2 6 oz. cans of hc 12a and the pressure 30 psi low side and 150-175 high side.

I have not finished mine yet, so this is not tested or working. I will follow up when I finish.

Steve

ssupercoolss

roadkill - mine was converted when i got it, so i havent really done anything to it except hook it up to my a/c machine. i mean, i know that my system has been vacuumed and charged properly since i did it myself, and have quite a bit of experience with a/c. i have converted many vehicles over to 134 with a great deal of success. i tell people to expect 50 at the vents when the vehicle is not moving. biggest problem with 134 is you gotta move air across the condensor. theres lots more heat and pressure associated with 134a. i have heard that there are a few different condensors for these vehicles. if i needed a new condenser, i would be looking for the biggest one i could stuff under the hood.

here are a few things to keep in mind. a converted system will actually require about 80% of the required r-12. and i have seen them work very well with less than 80%. there is sweet spot as far as how much to put in...the manufacturers "suggestion" is written somewhere on the vehicle. too much is usually worse than to little. on a cool morning you should be able to get a much lower vent temp. if not, your system is messed. start over. you will not have a good working system without first putting the system under vacuum. and the one that most people dont get the first time around, you will not have a good working system without first putting the system under vacuum.

jdw1

i didnt do it in that order. we pulled a vaccum on it for 2 hours then put about two can of freeze 12 in it and checked the pressures. seems like it gets cooler when i have the fan speed on a lower setting. also, when i cut the system off i can hear a noise coming from the evaporator. is this noise normal after you shut the system off? maybe its depressureizing or something?

toddowaddo

What kind of pressures are you getting? Evaporator noise does happen. Your temps will be colder at lower speeds, the air is spending more time through the evaporator and getting colder if that makes sense.

toddowaddo

I've converted a few vehicles to Freeze 12. I remember the first time I filled the system by weight, ie 10% less than R-12 capacity as recommended and it was overcharged. I had to reduce the amount. I've always gone by pressure since then. Around 20% less was better. This was on some old Benz's not a Toyota.

InternetRoadkill

I did the conversion on mine including vacuum for an hour, and it doesn't exactly freeze you. But my other car's a/c is totally dead so I can't complain too much. I'm running 25psi on the low side which seems to work better than 30psi which suggests that 134A doesn't want a lot of low side pressure on converted units. I'm afraid to set it much lower for fear of tripping the low-pressure safety switch.

Robrt32

I have said this before and most AC people will tell you what i did won't work and it may not for you but mine did.. I bought a used compressor off a motor in a dude backyard.. 20 bucks... I put it on and charged it with 2 can of 134 and a can of oil.. 37 at the vents going down the road.. no vacuums pulled and no fancy gauges.. this is the third summer since i done this... I had a few issues at first with the adapters, the one in the kits are junk IMO.. I bought from John Deere and problem solved