QuestionQUESTION: Hello Kevin. In May the HVAC in my Dodge gr Caravan stopped blowing cold air with A/C button pushed. A/C compressor clutch engaged continously (no cycling)but the low side line was warm not cold. I figured out that system is low on A/C coolant and added 1 can of R-124a (340g)coolant with dye without checking the pressure (I used the low side to charge the system). During the charge the compressor start cycling and low side line got cold. HVAC start blowing cold air again. After I finished charging I observed a few bubbles coming out of the low charge valve (I think is called Shrader valve) but I did not change it.
Fast forward 2 months.HVAC cooling performance got worst gradually until it started blowing warm air again.
Checked the compressor clutch and it was engaged all the time (no cycling). Hooked up A/C gages. With the A/C OFF presure was 90PSI om low side and 85PSI on HI side. With the A/C ON (clutch engaged)Low side 30-35PSI and HI side 190-200.
Turned engine OFF connected vacuum pump and took the pressure down to 0PSI on both sides. Replaced the Schrader valve with a new one. Connected the vaccum pump again opened both Low and Hi valves and vaccumed 45 minutes at a minus 28HG. After 45 minutes turned OFF pump closed the vales and waited about 15 min to see if the system holds pressure and it did. Disconnected the vacuum pump and start charging the system. I used 3 cans of R 134a 360g each. The label is asking for 940g for the entire system.All 3 cans were empty when I finished.
Noe I strted the engine and checked the pressure with engine ON Low side 35PSI HI side 210PSI.
Now the problem is that the compressor clutch is not cycling
(is engaged all the time) and cooling performance is still llow. It does blow cold air but not as cold as it was before all this started.
Do I need to add more R-134a?
Sorry for the long letter.
Thank you for your help.
Adrian.
ANSWER: do u have the cabin air on rec? have u found the original leak that u had to put the one can in the first time?
---------- FOLLOW-UP ----------
QUESTION: Thank you very much for your quick answer. In my first question I described in detail what I did. The leak was in the Low side charge valve and I replace that before I vacuumed and recharge the system. I forgot to mention that the engine is 3.3L with A/T
Yes I put the cabin air in recirc. I tried with the cabin air in all possible position and the performance is still not where it was before I started. One thing I have not done is wight the cans before charging the system.I went by the wight on the can's label.
My question again: Please see the pressure reading in my first question.Is this pressure enough or I should add more R-134a? Thanks again for your time.
Answerhow are u gauge the performance of the system??? u have dual air i take it? get a manual or digital thermometer and put it in the center vent u should have 40s to 50 coming out of that vent when driving. I saw all of the reading and it looks fine. Here is a pressure chat u compare it to what u have.
A/C PERFORMANCE TEMPERATURES
AMBIENT TEMPERATURE 21°C (70°F) 26.5°C (80°F) 32°C(90°F) 37°C (100°F) 43°C (110°F)
AIR TEMPERATURE AT LEFT CENTER PANEL OUTLET 1-8°C (34-46°F) 3-9°C (37-49°F) 4-10°C (39-50°F) 6-11°C (43-52°F) 7-18°C (45-65°F)
COMPRESSOR DISCHARGE PRESSURE AFTER THE FILTER DRIER 1034-1724 kPa(150-250 PSI) 1517-2275 kPa(220-330 PSI) 1999-2620 kPa(290-380 PSI) 2068-2965 kPa(300-430 PSI) 2275-3421 kPa(330-496 PSI)
EVAPORATOR SUCTION PRESSURE 103-207 kPa(15-30 PSI) 117-221 kPa(17-32 psi) 138-241 kPa(20-35 PSI) 172-269 kPa(25-39 PSI) 207-345 kPa(30-50 PSI)
plus have u done a recal of the doors and such?
COOLDOWN TEST ENTRY
TO INITIATE TEST:
Set Blower motor ON HIGH
Open all A/C outlets
Depress A/C and WASH buttons simultaneously for 5 Seconds (Until all LED's light)
RESULTS:
All LED's will turn on for 5 Seconds.
Cooldown test is running if A/C and RECIRC are alternately flashing.
Acceptable result is when LED flashing stops.
Calibration Diagnostics and Cooldown must be run separately.
