2001 Dodge 3500 a/c

etcarl · 08-02-2009, 01:32 AM

My a/c blows real cold for a indefinate time sometimes a long time sometime a short time THEN it gets warm for a indefinate time sometime a long time sometime a short time if I stop and turn the truck off to fill up or something else and restart it always starts blowing cold. What could it be?

bradrhale · 08-02-2009, 07:19 AM

does it blow warm or hot?? does it blow very much at all when it stops blowing cold??

etcarl · 08-02-2009, 09:33 AM

It blows strong fan motor is OK, It gets warm then blows temp the same as outside air.

bradrhale · 08-02-2009, 12:05 PM

have a pressure check done on the system and get back with the readings. only other things that i can think of is a problem with a connection somewhere.

etcarl · 08-11-2009, 07:16 AM

The low side is 33-34, the high side is 300.

bradrhale · 08-11-2009, 08:14 AM

high side is way too high. your high pressure switch is cutting it off.
possible problems:
fan clutch is not holding enough to pull an adequate amount of air through the coils
condensing coils are clogged and/or dirty not letting adequate heat dissapation

it is possible that the oriface has become clogged but this will only be the result of your compressor eating itself. since your pressure is so high, i would suggest dismissing this idea.
does your truck run hot in stop and go traffic, or at least, hotter than normal??

etcarl · 08-18-2009, 11:08 PM

The Cummings engine runs at normal to less than normal temp all the time.
If you are talking about the AC getting hot in stop and go traffic, that is not the issue the AC blows real cold for a period of time then gets warm to real warm. No matter what type of traffic. Then if I turn it off for a while say 5 minutes then turn it back on it gets real cold for a period of time 10 to 20 minutes then starts getting warm and warmer.

BernieB · 08-18-2009, 11:27 PM

Brad is right, the high side is too high and the high side safety switch is cutting off the compressor.

Any damage or debris on the condenser fins? When was the last time the A/C was serviced, if ever? Anyone try to add freon to the system? (Could be overcharged)

Also, as Brad says, it could be the orifice is getting clogged. Usually that happens when the compressor starts to fail, but I've also seen it happen when the desiccant bag in the accumulator (receiver/dryer) ruptures and the powder starts leaking out. The most common cause of that is a system that was opened and then not properly purged of moisture by putting it under hard vacuum for an adequate amount of time to boil off the moisture. The moisture then reacts with the freon, creating an acid that eats the bag.

etcarl · 08-23-2009, 11:16 PM

Thank You all for all your input.

bradrhale · 08-24-2009, 11:48 AM

what have you found so far?? fix the problem, maybe??

08-02-2009, 01:32 AM	#1
etcarl Junior Member Join Date: Aug 2009 Posts: 8	2001 Dodge 3500 a/c My a/c blows real cold for a indefinate time sometimes a long time sometime a short time THEN it gets warm for a indefinate time sometime a long time sometime a short time if I stop and turn the truck off to fill up or something else and restart it always starts blowing cold. What could it be?

08-11-2009, 07:16 AM	#5
etcarl Junior Member Join Date: Aug 2009 Posts: 8	Readings The low side is 33-34, the high side is 300.

08-18-2009, 11:08 PM	#7
etcarl Junior Member Join Date: Aug 2009 Posts: 8	engine temp The Cummings engine runs at normal to less than normal temp all the time. If you are talking about the AC getting hot in stop and go traffic, that is not the issue the AC blows real cold for a period of time then gets warm to real warm. No matter what type of traffic. Then if I turn it off for a while say 5 minutes then turn it back on it gets real cold for a period of time 10 to 20 minutes then starts getting warm and warmer.

08-18-2009, 11:27 PM	#8
BernieB Senior Member Join Date: Jul 2009 Location: Fredericksburg, VA Posts: 1,901	Brad is right, the high side is too high and the high side safety switch is cutting off the compressor. Any damage or debris on the condenser fins? When was the last time the A/C was serviced, if ever? Anyone try to add freon to the system? (Could be overcharged) Also, as Brad says, it could be the orifice is getting clogged. Usually that happens when the compressor starts to fail, but I've also seen it happen when the desiccant bag in the accumulator (receiver/dryer) ruptures and the powder starts leaking out. The most common cause of that is a system that was opened and then not properly purged of moisture by putting it under hard vacuum for an adequate amount of time to boil off the moisture. The moisture then reacts with the freon, creating an acid that eats the bag. __________________ If the guys who design 'em had to take one home, use it every day for 2 years, and do all the maint and repairs themselves, cars would have a button on the dash to change the oil, filters & plugs.

08-23-2009, 11:16 PM	#9
etcarl Junior Member Join Date: Aug 2009 Posts: 8	Thanks Thank You all for all your input.

08-02-2009, 07:19 AM	#2
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,021	does it blow warm or hot?? does it blow very much at all when it stops blowing cold??

08-02-2009, 09:33 AM	#3
etcarl Junior Member Join Date: Aug 2009 Posts: 8	It blows strong fan motor is OK, It gets warm then blows temp the same as outside air.

08-02-2009, 12:05 PM	#4
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,021	have a pressure check done on the system and get back with the readings. only other things that i can think of is a problem with a connection somewhere.

08-11-2009, 08:14 AM	#6
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,021	high side is way too high. your high pressure switch is cutting it off. possible problems: fan clutch is not holding enough to pull an adequate amount of air through the coils condensing coils are clogged and/or dirty not letting adequate heat dissapation it is possible that the oriface has become clogged but this will only be the result of your compressor eating itself. since your pressure is so high, i would suggest dismissing this idea. does your truck run hot in stop and go traffic, or at least, hotter than normal??

08-24-2009, 11:48 AM	#10
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,021	what have you found so far?? fix the problem, maybe??

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