Performance and Accessories 2nd gen only Talk about Dodge/Cummins aftermarket products for second generation trucks here. Can include high-performance mods, or general accessories.

a/c techs queston

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Old Aug 15, 2011 | 11:15 PM
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oldblues's Avatar
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From: s .e. pa.
Question a/c techs queston

hi
a/c compressor cycling repeatedly and ac not cooling ?

first thing comes to mind is low charge ??? maybe???

history
a/c worked great till sitting in traffic 100 deg day app last mounth and rubber line burst .

replaced line , vacuumed 45 min let sit 45 min no leak detected and recharged .

agin working great on 100 deg days , blowing 40 deg air .

noticed slower to cool last day or two but would get cold after slightly longer time ?

stuck a quick tester on while running and needle in middle of blue area so it still is charged according to this gauge ?

could my low preasure switch be bad? how do i test it ?

all positions on controles work!

any ideas ?
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Old Aug 17, 2011 | 11:47 PM
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If the ac comp is engaging than the low pressure switch is good, as far as it cycleing repeatble rule of thummb 7 to 10 times a min is correct, sounds like your charge is not correct, youu reallyy need to get gauges and see where the hi side is at, don't. Trust the autozone special gauge also what kind of refrigerant did you use, was. It a precharged with oil if so youu couuld. Have to much oil in the system makken stuff go stupid
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Old Aug 18, 2011 | 02:03 AM
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From: Kamloops BC
Originally Posted by 59shaker
If the ac comp is engaging than the low pressure switch is good, as far as it cycleing repeatble rule of thummb 7 to 10 times a min is correct, sounds like your charge is not correct, youu reallyy need to get gauges and see where the hi side is at, don't. Trust the autozone special gauge also what kind of refrigerant did you use, was. It a precharged with oil if so youu couuld. Have to much oil in the system makken stuff go stupid
what he said.

could also be non condensibles in the system.

45 min on vaccum pump dont mean anything..
how many microns? correct vaccum is whats important.
all that autozone gauge and refigerant drop in stuff is all crap

iam not going to argue like i have already done in previous threads.
bottom line
correct equipment/refrigerant/oil is all needed to make it work %100%
the autozone method "likely" will get you a 70% a/c

iam all about the DIY.
get a set of guages,vaccum pump, micron guage,nitrogen,refigerant
and ill guide you through it.
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Old Aug 18, 2011 | 09:39 AM
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Nitrogen is a good way to find leaks or dye, just cause. It held a vacume don't mean there is a leak. The system needs too charged to find a leak more than likely its a seal leaking if your low on charge. Recharged refrigerants. Are not good to use cause it will put excessive amouunts oof oil inn the system, I have had this happen many times, like lucas1 stated good tools and products pproduce good results
lucas1 micron gauge? Please explain
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Old Aug 18, 2011 | 05:19 PM
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From: Kamloops BC
Originally Posted by 59shaker
Nitrogen is a good way to find leaks or dye, just cause. It held a vacume don't mean there is a leak. The system needs too charged to find a leak more than likely its a seal leaking if your low on charge. Recharged refrigerants. Are not good to use cause it will put excessive amouunts oof oil inn the system, I have had this happen many times, like lucas1 stated good tools and products pproduce good results
lucas1 micron gauge? Please explain

micron guage = vaccum guage

below 29.92" of mercury vaccum..............microns are a form measurement.

if you dont evacuate(vaccum) to less then 1000 microns and it hold then you have a leak/moisture in the system.That is the route of most problems. non condesibles ie air
creates higher head pressure and compressor discharge temps,altimitly creating compressor failure.


i would NEVER!!!! add that can ****..

think about it if its low on gas...............potentially and likely a compressor shaft seal- in winter when the clutch cycles on defrost it is "sucking" in air and moisture.The next summer you flip on the a/c and "it dont cool" complaint pops its ugly head.

now if you go to wally world and buy the crap in a can you take it home guess the amont you need and stuff er in.........IT will cool,not well at all but will cool. but your compressor runs hot and your system is NOT running at 100%


my A/C in all my vehichles will freeze you out....................i also put colder thermostats in


ice on the inside of the windows
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Old Aug 18, 2011 | 06:29 PM
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From: Madison, WI
Talking

Originally Posted by 59shaker
Nitrogen is a good way to find leaks or dye, just cause. It held a vacume don't mean there is a leak. The system needs too charged to find a leak more than likely its a seal leaking if your low on charge. Recharged refrigerants. Are not good to use cause it will put excessive amouunts oof oil inn the system, I have had this happen many times, like lucas1 stated good tools and products pproduce good results
lucas1 micron gauge? Please explain


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Old Aug 18, 2011 | 06:35 PM
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Ok I understand now and follow, I am spoiled cause I have access to a robinair machine that makes life alot nicer, it does it all and monitors for leaks ii have had it pass the leak test and it had a leak had to pressured the system to find it cauuse under vacuum it held
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Old Aug 19, 2011 | 04:39 PM
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From: Kamloops BC
usually its the other way around.
ive seen a leak under vaccum and not under pressure.


and for the record ive been out of school a while
29.99" is perfect vaccum

but do you see why its imparative to evacuate to ..........below 1270 on the chart..
all the moisture boils off....and out of the oil
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Old Aug 19, 2011 | 05:01 PM
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I don't know about the front pump seal I ment in general That's what I have seen, but yes getting the system down to 1270 microns is inportant and makes since cause boils off moisture that's also why it is recommend To change The dryer everytimethe system is opened too help prevent moisture Issues
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