Okay, here's the problem... The AC on my '04 Coupe started blowing hot. I recharged the freon, checked the vacuum line (it's good), put it all back together and still no cold air. I felt the hoses on either side of the expansion valve and the inlet is considerably warmer than the outlet side. I replaced the valve, but the problem persists. Anyone have a suggestion as to what's wrong?

 

Did you put gauges on it and actually check pressures? What is the vacuum line?

 

Can you confirm the compressor crankshaft is turning when the clutch is energized???

Does the engine slo with the INCREASED LOAD on the engine, proving that the compressor is taking power??

Does the fan come on to indicate that the a/c switch is correctly sending power to the compressor and fan?

The discharge line on the compressor should show heat even with a plugged orfice for a few seconds due to the heat of compression and compressor losses.

Let us know, and gauges should show a high hi and lower lo if only for a short time. Also your dryer could have moisture and be clogged, did you evacuate the system after the repair/fix.

Woody

 

Sounds like the dessicant in the dryer has gone bad. I would replace the dryer. JMO.

 

Woody,

Thanks for the suggestions, and in answer to your questions, 1,2,3, and 5, Yes. As to #4, the line does as suggested.

Further to #5 I have now evacuated the system and checked for a clogged dryer three times, and still no cold air.

Anyone have any ideas as to what I am overlooking?

 

THe expansion device, tube could be clogged, see if the screen is clogged and while it is apart, blow thru the lines with air or freon to confirm that the passages are not clogged. If the pump pumps , the gas has to go in a circle and that should cool the car at least some. Pressures could be helpful in this study, Woody

 

Just a suggestion. Replace the dryer because you cannot tell if it is bad by visual inspection. As Woody and I mentioned the dessicant could not be any good. JMO

 

Woody and Warren, I'll try both of your suggestions over the weekend and report back...

 

Okay, the lines have been flushed (third time since I started on this) but the compressor still only runs for about two minutes, the air blows cold, and then pressure build up in the line causes the compressor to shut down. Once the excess pressure bleeds off the compressor kicks back in and the unit blows cold for about two minutes before the compressor again shuts down. The problem seems to be the expansion valve as everything else seems to check out okay; I've now replaced the valve twice but the problem still persists. Is it possible that both the Chrysler dealer and aftermarket expansion valves I've bought are faulty? Although I doubt it, would a MBZ valve be a better choice, or could someone recommend another source of valves?

 

50 years in HVACR. I recommend you clean the condenser at the car wash. I do it annually. gary

 

If you have fixed the valve twice, its not the issue. YOu have not given pressures _YET.

If your going out on high head, decrease,reduce, remove some of the charge. Are you charging by weight after evacuation?????????? Add less charge, dont fall for the label, it might not be accurate - at least you can add less charge and go from there. Clean the radiator coil as suggested also..

Woody

 

Okay, I'll give it a shot at the car wash (gee, wouldn't it be great if that was the problem). I'm not sure as to the pressure, but off the top of my head I think it read 125 psi-- I'll double check on Monday and report back. I'll also reduce the charge (after I try the AC with a clean condenser).

Thanks guys, I really appreciate the help you've given me.

~Scott

 

So, what are you using to charge it? Please tell me it's not the little plastic gauge that comes with a can of 134 at the parts store.

 

You forgot to mention.....throw in a pinch of Epsom Salts for good measure.

 

Exactly, Those can guages can get you overcharged and still read for more. Thus kicking out the compressor.

 

All part of self reliance. I still have and use R12 in my cars.Epsom salt in my body They provide highest performance. gary

 

Still haven't solved the problem. I've replaced the pressure relief valve; I have purged the system and replaced the freon; I removed the grill and cleaned the condenser. The compressor comes on as it should. Checking pressure the low side pressure is 120, the high side is 400. After running for approximately 2-3 minutes the compressor shuts off.

Can you guys think of anything else I should try?

 

I think it is time to check the sensors in the system, I know squat about it but maybe the compressor is getting a signal at the wrong time, or an erroneous signal. Get the multimeter out and start checking the circuits. See the repair manual.

 

400# is a bit high on the discharge side. When the compressor kicks off, what is the reading on the high side? Does it stay up? Come down slowly? How much time does it take for the pressures to equalize? 10 seconds? 5 minutes? It's sounding like the liquid line is restricted.

 

400 !!!!!!!!!!!!!!!!!!! Drop the charge, you got too much 400 is high for a r22 system. How much are you adding anyway, should be ounces??????????

Compressor is fine, you are overcharged like a sumbitch............Let us know, and I hope your using R134a????????????????


Let us know what is going on, 120 is high too.............that is a boiling point of 98 degrees

use this chart and let us know how much of what your using.........

R134a Refrigerant Pressure Temperature Calculator