2nd Gen Non-Engine/Transmission Why won't it cool,A/C

[DickersonD]

I have a 94 with a one year old compressor that shows,with gauges to be cycling properly,and it won't blow any colder than about 70 degrees unless its early morning and cool out side,then it will blow 40 degrees. I had dodge check it out and they fixed a loose high pressure switch connection but other than that could find nothing wrong. The dryer and compressor were both replaced about 18 months ago and it has never seemed as cold as it used to be but now it is unbearable if the outside temp is anything over 80 degrees.

Any ideas or simular problems?

 

[Neibe]

Mine wasn't cold and I bought a can of refrigerant and put that in and know it is cold. But I would assume the dealer would have checked that out.

 

[Matthug]

Hey I had this trick me just this week, check to see if this happened to you- The cable that operates how hot or cold it is the tab on the back broke and the cable wasn't going all the way. The dial showed that I was on full cold but it was actually about halfway. I had it blowing about 65 degrees out the vent, not good for temps over 80 also. But now it's fixed and cold again!

 

[Matthug]

Oh and also check the pressure on the system while it's running, should be 40-50 PSI or so, if less than 40 you need more refrigerant. Any parts store like advance or autozone should have the gauge.

 

[DickersonD]

I have enough freon in it going by the gauges,but i'll check out the temp selector but I don't think thats it since it will get cold in the morning. thanks

 

[DickersonD]

I don't see a cable for the temp selector all I see are vacum lies were is this cable?

 

[GAmes]

How long has it been since you cleaned the bugs and road grime from the coils in front of the radiator? Also, is the fan clutch working and spinning the fan fast enough?

 

[Matthug]

I don't see a cable for the temp selector all I see are vacum lies were is this cable?

The vacuum lines are at the top of the controls, look at the bottom there will be white plastic gears that move up and down and a black coated cable hooked up to it.

 

[WA5LTA Bill]

I have a '99 2500 with similar A/C problems. It cools good early in morning with selector set on MAX cool. I checked refrigerant line temps a bit earlier this afternoon with the engine idleing (it had been setting all day and had started it just before making checks). These are temps that I recorded:



Outside air entering condenser with hood up: 87. 4

Cab temp: 95. 5

Supply (vent) temp: 84. 4

Comp disch temp (entering cond. coil): 121

Liquid line leaving (at schrader port): 101. 5

Liquid line between battery and engine air filter: 82. 8

Liquid line entering firewall: 80. 1

Suction line (at schrader port): 80. 6



I didn't check the heater hose temperatures, but when I shut down the engine, I felt of both of them and they were hot.

 

[Missouri Mule]

Your evaporator could be freezing up. Mechanic told me high pressure could do this but he mite of meant low pressure switch (He said switch could be adjusted. High pressure switch is set at factory low pressure switch is adjustalbe according to service manual).

 

[Matthug]

The temperatures of the lines has nothing to do with anything, you need to check pressure.

 

[WA5LTA Bill]

Matthug, I beg your pardon, but refrigeration is all about temperatures. I'll agree that I need to check the operating pressures, but I don't have a R-134A manifold. I've been in residential/light commercial HVAC for over 30 years. I'm not very well versed in automotive A/C. I am just trying to determine what to look for in the way of possible problems. One aspect of the temperatures that has me concerned is the 18. 7 deg drop in the LL within 18" of the condenser outlet and the additional temperature drop before entering the firewall and into the evaporator. Is there a filter/drier inline that I'm overlooking?

 

[GWilber]

The liquid line has an orifice tube made into it. It is non-serviceable and the whole line has to be replaced. I bought mine from a local wholesaler last week for $22. Replacing it helped, but I'm afraid the evaporator coil is plugged with dog hair. Does anyone know how to clean it without pulling the dash?



Greg

 

[Matthug]

Matthug, I beg your pardon, but refrigeration is all about temperatures. I'll agree that I need to check the operating pressures, but I don't have a R-134A manifold. I've been in residential/light commercial HVAC for over 30 years. I'm not very well versed in automotive A/C. I am just trying to determine what to look for in the way of possible problems. One aspect of the temperatures that has me concerned is the 18. 7 deg drop in the LL within 18" of the condenser outlet and the additional temperature drop before entering the firewall and into the evaporator. Is there a filter/drier inline that I'm overlooking?

Any autozone or advance should have the gauge... . it a line that hooks up to a refrigerant can but it has a check valve in it so you don't have to put on a can just hook it up to the low pressure hose (top hose) port. Without the A/C on it should be probably around 80 PSI or so, with it on anywhere from 40-55 is good.

I have never heard of anyone diagnosing an automotive A/C system by checking the lines temperature.

 

[JohnMcIntyre]

Sounds like you gotta leak somewhere and you're losing R-134 gas... slowly at least!! Do you know for sure whether you're still fully loaded with around 0. 909kg approx? ( a full fill FYI ).



Why not try getting a fluoresecent tracer dye mixed in with the gas, and use an appropriate light source under the hood, to see if you have any sort of leak... . ??



Don't believe all the hype/bull**** - you might get from an AC station either; just because they can pull vacuum on all the seals (big deal!), when they pressurise the system with R-134, these same seals -even if they're a bit flaky - will leak refrigerant gas like it 's going out of fashion!!



Hey it's a bummer and I've already got the T-shirt!!



Oh not wanting to sound crass or unhelpful - see my words above first - but when does a faulty AC system mean you're 911?? Help me out here - it's all relative!!



Apart from that it's been emotional!!

 

[EricBu12]

The last leak I had was at the pich connector on the low side just under the insulation wrapping where the hard line goes to a rubber flex line..... It was leaking right at the top of the joint between the crimp part and the hardline... . I used JB-Weld on it and letit cure overnight... then charged it up. . has held pretty good since.

 

[Matt42]

Warm Air From AC

I have a 94 with a one year old compressor that shows,with gauges to be cycling properly,and it won't blow any colder than about 70 degrees unless its early morning and cool out side,then it will blow 40 degrees. I had dodge check it out and they fixed a loose high pressure switch connection but other than that could find nothing wrong. The dryer and compressor were both replaced about 18 months ago and it has never seemed as cold as it used to be but now it is unbearable if the outside temp is anything over 80 degrees.

Any ideas or simular problems?

A few things to look at: Feel (carefully) the suction and discharge lines coming off of the compressor. If all is well, the discharge tube should be warm to very warm, and the suction line should be cold. If the suction line is warm, the most likely causes I have found are not enough R-134, too much R-134, or moisture in the system.



The snap connection between the receiver-dryer and the evaporator is a difficult one that looks easy. It has to physically and audibly make a *click* sound when the connection is made. The retainer clip will still fit fine over an inadequate connection, so that is not any quality control check. Even if the connection is not positive, it is possible for the system to evacuate and hold vacuum for half an hour or more, but it will not hold the operating pressure. Worse, if at some time in the truck's past a non-MoPar evaporator was installed under the dash, the connection may actually be impossible to make. You may be able to use an electronic leak detector here with a full charge of R-134.



The condensor in front of the radiator contains a plastic orifice with a mesh filter. It is in the tube that is vertical coming out of the condensor. Over time, the filter and orifice will plug up with the result that the AC output is warm. The only way to tell is to open the system and look. (You'll need a set of Ford-type tube-release tools, which will set you back less than $20. ) According to D-C, the orifice is not serviceable. I have found that it can be removed with some patience, some denatured alcohol, and a pair of fine needle noze pliers. It's a press fit in, and will pop out once the stuff that looks like charcoal is removed. Clean the orfice and filter screen thoroughly--it's not an individual part. Be sure to flush the condensor with denatured alcohol, then blow out with DRY compressed air. The fastest way is to just replace the condensor, though.



Before you do anything that involves surgery, check the condensor, intercooler and radiator for bugs and dirty oil.



Back in the R-12 days, it was OK to overcharge the system a little bit. That's not so with R-134. Too much refrigerant will really reduce cooling.



Good luck!

 

[Matt42]

Sounds like you gotta leak somewhere and you're losing R-134 gas... slowly at least!! Do you know for sure whether you're still fully loaded with around 0. 909kg approx? ( a full fill FYI ).



Why not try getting a fluoresecent tracer dye mixed in with the gas, and use an appropriate light source under the hood, to see if you have any sort of leak... . ??



Don't believe all the hype/bull**** - you might get from an AC station either; just because they can pull vacuum on all the seals (big deal!), when they pressurise the system with R-134, these same seals -even if they're a bit flaky - will leak refrigerant gas like it 's going out of fashion!!



Hey it's a bummer and I've already got the T-shirt!!



Oh not wanting to sound crass or unhelpful - see my words above first - but when does a faulty AC system mean you're 911?? Help me out here - it's all relative!!



Apart from that it's been emotional!!

I have to agree about the seals holding vacuum but not pressure. After an episode of that with the drier-evaoprator connection (see above) I made sure it would hold vacuum for--no kidding--18 hours. Then it was fine.



As for air conditioning being a 911 thing, it's relative. `Round here, a functioning air conditioner is as useful as a funtioning heater in Fairbanks, Alaska. In a prior job in 1984, in the low desert in California, I came upon a nice family from Amsterdam whose rental car had broken down on a road that didn't get much traffic. It was 45 degrees Celsius outside, and one of the party had started off on foot for help. The nearest phone was 15 miles away. I was driving a full size Jeep Cherokee with a 258 six, a good air conditioner, and a cooling system the size of Baltimore. The man walking--a physician--was in the early stages of heat exhaustion, and knew it. He would have died making that walk. I drove him back to his family, and put them all in the Jeep. I idled the Jeep's engine and ran the air conditioner on full to get his body temperature back down to a safe range. Meanwhile, I got on our radio system and had Dispatch notify the car rental company, who got right on the situation. The family had a little bottled water with them, since American water had given them intestinal problems. After about an hour, the rental car company had a tow truck on the way, from a location about 50 miles away. A California Highway Patrol officer arrived about an hour later. He and I discussed the situation, and he agreed to stay with the family until the tow truck arrived. At this point, the Jeep had been idling with the air conditioner on full for two hours, and no sign of overheating.



In this case, water was the key element, but the air conditioning prevented additional trouble. I've never forgotten that incident.