Hello and thanks in advance:

What is the approximate temperature you want blowing from your A/C vents. 80 outside temp, I have on the low setting, low fan speed, center vents 36 degrees. I did a repair on an old vehicle and used a Freon Replacement, and didn't weigh the charge. I used the manifold guages and had a reading of about 36 on the low side, 225 high side, at idle.

Thanks
Frank D

 

36 degrees is good, might be a little too good at a highway cruise with the fan set on low, the lines may freeze up. Generally speaking, 50 degrees or lower at the vents is good to go.

 

When checking the Vent Temps, take your reading at the Center Vent with A/C set to MAX COOL with the Blower on HIGH SPEED, windows up. Vehicles and A/C's vary, so the following is just a guidline. With the vehicle parked in the SHADE, after the A/C has run a few minutes and stabilized, take the Vent Temp at the center vent at Idle speed and then at 1500 rpm. If the A/C is working WELL, it should be 50 or colder at idle and 46 or colder at 1500 rpm at outside air temp of 90. If outside air temp is 100, you should expect 55 at idle and about 50 at 1500 rpm. Also check the temp at each vent, as there should not be more than 3 degrees variation between them. If there is much variation, there may be a problem with the air distribution in the A/C ducts or actuator doors. It's also a good idea to leave the dial thermometer in the center vent and drive it around for a while, to see how the vent temp behaves under different driving conditions. Driving down the road, you should see 46 to 50 degrees. 55 would feel cool but not cold, 60 would feel not as cool and would warrent checking the sytem and repair.
Good Luck.
E.D.

 

Very hot here now, tested A/C in full size van. Had it parked in the shade 90*, managed to get 52* vent temp at idle and about 48* at 1500 rpm. Total time running 5 minutes, fan set high, max A/C.

 

The Temps don't look bad considering the Ambient Temp and the High Humidity. Also, it takes more time to cool down a van, simply because there is a large volume to cool. I would think that if you get on the road, that it will cool better than 48 degrees. If it seems to take longer to cool down than it used to, first check the fan and the air flow thru the condenser. Clean the condenser to be sure it allows air to flow freely thru it. You need to move a lot of air thru the condenser for good cooling. If the A/C has not been serviced for a long time, and you want to go into it further, it may have moisture in the system. Discharge and recover the refrigerant, pull and check the orifice tube. If dirty and/or partially clogged, remove the accumulator, flush out the condenser, hoses and evaporator, and blow them out dry. Do not flush the compressor, just take it off and drain out the oil, pour some new oil into the suction port while turning the compressor hub by hand, to help rinse the old oil out. After it's all clean and drained out, put about 4 ounces of new oil in the compressor, 1 ounce new oil in the condenser, and put 3 ounces new oil in a new accumulator and put everything back together with new o-rings. Check the specs on your vehicle for the correct amount of oil charge. Turn the compressor hub by hand at least 15 times to clear the oil from the valves. Put guages on system, evacuate in deep cycle for an hour, then charge new refrigerant into the vacuum, start engine, A/C on MAX Cool, High Blower, windows up, Engine at 1500 rpm, vehicle in the shade, continue to charge in the correct amount of refrigerant. Observe pressures to be sure they are correct, FEEL the temps of lines to be sure they are correct also. You may also use an infrared thermometer to check line temps. On a hot day, 90 degrees +, the line from compressor to condensor should be too hot to hold (200 degrees or more), the line from condenser outlet to o-tube at evaporator inlet should be warm (about 140 degrees), Evaporator outlet tube, accumulator should be cold (about 40 to 50 degrees) and the suction line to the suction port on the compressor should be cold (varies with amount of charge, about 50 to 60 degrees). Put the last part of the charge in VERY slowly and feel the temps of the lines. Pressures should run between 22 to 30 on the low side and between 225 to 240 on the high side. On retrofits on older vehicles, you may get higher high side pressures due to the older condensers being smaller. As you are charging VERY SLOWLY, you should feel the cold at the evaporator outlet first, then the accumulator gets cold, then the cold moves up the suction line towards the compressor. The best charge is usually when the cold JUST reaches the suction port of the compressor. If you put a little "extra" charge in, it won't make it colder, it will raise low side pressure and reduce the cooling, so DON'T overcharge. Overcharge is worst than undercharge.
Good Luck
E.D.

 

Thanks E.D for your time and a very informative reply. This vehicle has a new evaporator, orifice tube, and accumulator dryer.

Long story short after 3 trips to a service station for leak repairs and about $400.00 Wasted I decided to grab my father in law (retired A/C tech), his tools, and find the leak. Bad evaporator, odd after 3 visits they couldn't have found it the first time, bbbbbbbbuuuuuuuuuuuttttttttttttttt, its water under the bridge now.

The only part I am missing is the high side service port cap. It mysteriously vanished at on of the trips to the service station. I have a make shift cap on it to keep dirt out. I leak tested the Schrader valve missing the cap, and it was not leaking. The part is on order from the dealer.

I am hoping nothing seeps out without the cap.

Thanks again,
Frank D