2nd Gen Non-Engine/Transmission Air Conditioning

[ctingler]

Good Morning,



Hoping for some help with an air conditioner problem. I have a 2001 Dodge 2500 Ram, 24 Valve. Have been having this problem since 2002, truck was bought brand new.



I have had the following done to my truck with no results. (1) Low charge (shot with dye) system held vacuum very small leak unable to locate, (2) There is a hot fluid smell when defrost is used, a film appears on the windshield, (3) When the A/C blower motor is on high, it vibrates badly, (4) A/C lines plugged replaced hose from cond. to vap, suctioned discharge assembly evac. and charged system, (5) Checked with black light and no visual leaks, (6) Removed dash found evaporator leaking, evac. system replaced evap. , recharged system and still has small leak, installed dye customer to return to check with light, (7) A/C blowing warm again, added dye, checked for leak and report, inspected system found no leak in system, recharged system and rechecked/cooling to 34 degrees, (8) A/C not cooling, (9) A/C inoperative, found charge low with black light found no dye in system. Evac. recharged system, installed 2. 0 oz. dye. Started to trace system with black light or sniff trace of freon at lines, evap, condensor, rec. /dryer, compressor, road tested to freeway speeds and stall ran 1. 5 hrs. reinspected complete system no leak present, tech. requested customer to take vehicle and drive til Monday and return for reininspection for dye trace. Vehicle cooled for about 3 months and again started blowing hot air.



Any help would be greatly appreciated.

 

[JDKammin]

Any idea what your low and high pressures are? Have you made sure your heater valve is shutting off completely? You can check that by grabbing the heater hose going to the firewall, which should be hot. If the heater valve is shutting off, the return side should be quite a bit cooler.

 

[fest3er]

Have you cleaned/replaced the low pressure and high pressure cutoff switches? Are you sure the compressor clutch is OK?

 

[Skydiver]

I have a Tech degree in AC/refrig from 30 years back.
A good sniffer with enough time and NO fans or outside wind will find the leak. I work in a lab and one of the things I do every day is "test the tester". These sniffer probes get shoved in some pretty grimey places. My favorite refrigerant locator was the propane torch type.
With as much dye that was injected sounds like your leak is inside the cab. When you say "the system held a vacuum", do you know for how many minutes after the vacuum pump was turned off ? Most auto/ac techs I've seen work on book time and only wait 15 minutes which is not enough. I like to leave them in a vacuum at least a few hours. A rising or falling ambient temp can affect a vacuum reading. If you pull a vacuum in a hot temp then it becomes cooler later on a tiny leak may become hidden by the system cooling down and contracting.
Take a high pressure air hose and clean the condensor. Sometimes a combination of problems can affect the efficiency of a cooling system.
Our trucks AC system (or any other refrigerant cooling system) does not cool anything. It moves heat,,,outside or inside.
.
I stock piled large quantaties of R - 12 years ago. Now I'm going to stock pile r134a. I bought some expensive American made R134 gages a few years back. My son works in the HVAC field and says in 10 years R -22 will be phased out.
Refrigeration theory simplified.

 

[ctingler]

Pressure at first was on low or zero and the condensor wasn't kicking on and then I put in 2½ cans of the 134 and it finally went up to 45. As of now it's staying in the blue at 45. Hopefully it will stay in. I checked hoses and all fittings and everything seems to be okay. I'll keep you informed as the weeks go by. Thanks for all your help and suggestions.