Air conditioning woes

[MSkyrman]

We are in Lewisville, TX (30 mi. north of Dallas) for the next couple weeks and need to get our AC troubles solved. If anyone has any recommendations with regards to repair shops and/or dealers service depts, would love to hear them. Here are the problems:



When we start out driving on a warm day, the AC will blow cold for about 20 minutes or so, then it will gradually start to get warmer, the fan will blow less, we'll have turn up the fan speed max, until we are getting hot in the cab. At this time the fan is making rather loud noises... vacuum-cleaner like noises. It happens to both the drivers and passenger sides. We've been experiencing it for awhile now.



Another symptom is that the AC will blow cold for awhile, then gradually blow warm air. We'll shut of the AC for about 30 seconds, then turn it back on and it will blow cold again (for awhile), until the same thing happens again.



Last time I scanned for DTCs, it showed one related to the AC clutch relay circuit (P0647).



I know so very little about the AC system, wondering if I am better taking this to the dealer (haven't been to one in years) or an independent shop.

 

[SHobbs]

I can recommend Alan Samuels, they replaced the dash top in my truck and were stellar. I don't normally recommend a dealer but these guys are good, fast too. You could search for that A/C clutch relay to see if it is available at parts houses and replace it. Might be a cheap fix.



Map and Directions to Allen Samuels Chrysler Dodge Jeep Alliance located in 11200 North Freeway Fort Worth TX 76177 888-655-9397



Scott

 

[SRadke]

Sounds like your cold coil is freezing up. Does it work longer if you don't turn it to full cold?

 

[MSkyrman]

I don't know, I would have to try that? I guess by force of habit, I have it set all the way to full cold in the summertime and usually adjust the fan speed to reach the right temperature in the cab.

 

[MSkyrman]

Thanks a bunch.

 

[LRutigliano]

We are in Lewisville, TX (30 mi. north of Dallas) for the next couple weeks and need to get our AC troubles solved. If anyone has any recommendations with regards to repair shops and/or dealers service depts, would love to hear them. Here are the problems:



When we start out driving on a warm day, the AC will blow cold for about 20 minutes or so, then it will gradually start to get warmer, the fan will blow less, we'll have turn up the fan speed max, until we are getting hot in the cab. At this time the fan is making rather loud noises... vacuum-cleaner like noises. It happens to both the drivers and passenger sides. We've been experiencing it for awhile now.



Another symptom is that the AC will blow cold for awhile, then gradually blow warm air. We'll shut of the AC for about 30 seconds, then turn it back on and it will blow cold again (for awhile), until the same thing happens again.



Last time I scanned for DTCs, it showed one related to the AC clutch relay circuit (P0647).



I know so very little about the AC system, wondering if I am better taking this to the dealer (haven't been to one in years) or an independent shop.

Your description is classic R-134a leakage. With 3rd gen trucks, leaks are very common. Combination of very poor designs for the fittings/seals and diesel vibration. Although, most common leak point is the compressor front shaft seal (very hard to diagnose due to the compressor clutch covering this area)



Another way to tell if you have the above issue to open your hood and look at the refrigerant liquid line (smaller dia line that go's to firewall) and you will see it completely covered in frost.



Go to any automotive store and purchase two cans (12oz each) of R-134a and an inexpensive kit to add the refrigerant to the low side of the system. Usually 1 can will fix it right up.



Many automotive stores also carry PAG oil in 3oz containers from Interdynamics. Installs the same way as the R-134a. You want the MEDIUM visosity (100 vis) PAG oil. When you lose refrigerant, you also leak oil and the compressor will eventually fail due to lack of lube.



Why does the air blow warm, then none at all?? Because the evaporator becomes a solid block of ice and blocks airflow and causes the blower to get very loud because the air has no where to go.



Doesn't make common sense, right?? Well, when you lose refrigerant, the suction pressure in the system drops very low. The lower the suction pressure, the lower the temperature (below freezing), hence the ice blockage. When you turn off the system, the ice melts and then you cold air again for awhile until the process occurs again.



Our trucks have evaporator freeze sensors that turn off the compressor when the air temp thru the evap gets too cold, however, when you have lost refrigerant, the cold spot in the core moves from where Dodge put the sensor to somewhere else in the core. The evap sensor doesn't get cold enough to turn off the compressor, even though some other parts or most of the evap starts to freeze. Dodge trusted the HVAC supplier and didn't do enough of their own development and testing to properly chase the coldest spot in the core when leakage occurs... It takes ALOT of testing to properly develop an AC system.



Hope this helps.

Louis

 

[BHanna]

Sounds like a leak to me too. Adding refrigerant is a band-aid though. You will want to take it to a shop with a sniffer who can find the leak and fix it. You may get lucky. On mine, I have a schrader valve that has vibrated loose a couple times now. The fix was easy. Just tightened it back up and added r134a.

 

[MSkyrman]

Your description is classic R-134a leakage. With 3rd gen trucks, leaks are very common. Combination of very poor designs for the fittings/seals and diesel vibration. Although, most common leak point is the compressor front shaft seal (very hard to diagnose due to the compressor clutch covering this area)



Another way to tell if you have the above issue to open your hood and look at the refrigerant liquid line (smaller dia line that go's to firewall) and you will see it completely covered in frost.



Go to any automotive store and purchase two cans (12oz each) of R-134a and an inexpensive kit to add the refrigerant to the low side of the system. Usually 1 can will fix it right up.



Many automotive stores also carry PAG oil in 3oz containers from Interdynamics. Installs the same way as the R-134a. You want the MEDIUM visosity (100 vis) PAG oil. When you lose refrigerant, you also leak oil and the compressor will eventually fail due to lack of lube.



Why does the air blow warm, then none at all?? Because the evaporator becomes a solid block of ice and blocks airflow and causes the blower to get very loud because the air has no where to go.



Doesn't make common sense, right?? Well, when you lose refrigerant, the suction pressure in the system drops very low. The lower the suction pressure, the lower the temperature (below freezing), hence the ice blockage. When you turn off the system, the ice melts and then you cold air again for awhile until the process occurs again.



Our trucks have evaporator freeze sensors that turn off the compressor when the air temp thru the evap gets too cold, however, when you have lost refrigerant, the cold spot in the core moves from where Dodge put the sensor to somewhere else in the core. The evap sensor doesn't get cold enough to turn off the compressor, even though some other parts or most of the evap starts to freeze. Dodge trusted the HVAC supplier and didn't do enough of their own development and testing to properly chase the coldest spot in the core when leakage occurs... It takes ALOT of testing to properly develop an AC system.



Hope this helps.

Louis

Louis, yes, that helped a lot. Thank you. I bought the refrigerant from Interdynamics at Walmart, it was one big can with the kit and even a pressure gauge. It also had the oil and even a leak sealer built into the refrigerant. It took most of the can, and as soon as I added the refrigerant, the white frosted line thawed out. It seems to be blowing cold now without interruption. Good air flow to floor, vents and defront. Pressure gauge is probably not accurate but read 35 psi (allegedly indicating a charged system), not sure how that compares with what is specified for the AC system. (??). Maybe I'll get lucky and the leak sealer will work, or least get a few months of AC for the summer before I need to go hunting for the leak. Thanks again.

 

[JFought]

i have had serious issues with both Allen samules... . lets just say dented and scratched door and a bar repair that led to an entire new rear axle assembly!!

 

[WM-300]

I have a 03 Ram with the same issues. I too will get the refill kit. It worked fine last summer/fall. Yesterday is the first time I wanted AC and it failed.



Where is the injection point where you add the refill charge



WM300

 

[Tejasdge]

When we start out driving on a warm day, the AC will blow cold for about 20 minutes or so, then it will gradually start to get warmer, the fan will blow less, we'll have turn up the fan speed max, until we are getting hot in the cab. At this time the fan is making rather loud noises... vacuum-cleaner like noises. It happens to both the drivers and passenger sides. We've been experiencing it for awhile now.



Another symptom is that the AC will blow cold for awhile, then gradually blow warm air. We'll shut of the AC for about 30 seconds, then turn it back on and it will blow cold again (for awhile), until the same thing happens again.

Mine did this also where it would stop blowing cold from being low on refrigerant. If you're stuck on the road in the middle of no-where, run it on max A/C to reduce humidity going across the evaporator and slow freeze up. When it starts to "loose it's cool", turn off the compressor, but leave the fan on. It will start blowing cooler (as the ice melts) and once warm air is blowing, turn the compressor back on.



A 134a refill kit is part of my travel kit now. Along with a spare belt, fuel filter, oil, trany fluid, duct tape, etc. , etc. , etc.

 

[MSkyrman]

I have a 03 Ram with the same issues. I too will get the refill kit. It worked fine last summer/fall. Yesterday is the first time I wanted AC and it failed.



Where is the injection point where you add the refill charge



WM300

If you are in front of the truck looking at the passenger side of the engine compartment, the low side port (on my truck it has a gray dust cap with the letter 'L' and the numbers '34' on it) is just to the left and below the transmission dipstick. It is very close to the passenger side battery.

 

[WM-300]

Thank you for the location.

WM-300