- This topic has 16 replies, 6 voices, and was last updated 12 years, 9 months ago by
.
-
Topic
-
so its kinda a long story but last year a hose leaked out the r134a out. I got a fancy gauge and vacuum pump. I replaced the hose. put a vacuum on the system. put in one can. can tap broke on the second can. ($2 ebay special) Left it till spring. probably not necessary to explain all that but now ya know.
any way I found a temperature / pressure chart online so I was going to fill it according to the temperature.
Just wondering if I should fill it at idle or at a certain rpm. my truck idles at about 500 rpms.
if it matters my truck is a 1998 gmc k1500 5.7L
Thank you for your time.
-
Replies
-
set the control to Max cool and fan on high speed. The truck should be at idle. The trucks Iac should boost the idle by itself.
. the best and most accurate way is to weigh in the charge. C8-)I’m trying to figure out what I’m doing wrong. I got the low pressure to where it should be but the high is still to low according to my chart. I notice when I rev the engine the low goes down the the high goes up.
I checked my moms honda accord because I know that ac works and it was the other way around the low pressure was to low and the high was were it was supost to be. I’m so confused.
The engines speed does not change when I turn on the AC it stays at 650rpm.
I just went for a drive and the air was noticeably cooler on full blast but not as cold as it should be.
What exactly are your readings on the gages?
How long did you hold vacuum in the system?
Did you recharge the system with the exact amount needed for your vehicle?
If you have low high side pressure readings, there could be several issues from icing evaporator, low freon to even a possible restriction.
Quoted From dreamer2355:
What exactly are your readings on the gages?
How long did you hold vacuum in the system?
Did you recharge the system with the exact amount needed for your vehicle?
If you have low high side pressure readings, there could be several issues from icing evaporator, low freon to even a possible restriction.
I just went out and put them back on to get a reading. The low side is 42 Psi and the High side is 112psi. and this is at 70 degrees F according to my chart the low should be 35-40 psi and the high 145-160psi
The capacity for my truck is 2 pounds 0 ounces. each can is 12 ounces so capacity is 2.67 cans. I had no way to exactly measure the cans but in November I put in 1.5 cans. The tap quit working half way though a can. It feels about half full when compared to a new one. than I put in one can today with a new tap.
every one else on the internet seamed to just keep a eye on the pressure when it reaches that pressure your done.
I pulled a vacuum for 30 minutes (owners manual said 15.)
Quoted From gaseousmercury:
Is the compressor turning on and maxing out at 112? is the clutch engaging on the compressor? Hows the belt tension? Was there any freon left in the sysytem for last year. Did you put in a new dryer or accumulator; I’m not sure which is on that vehicle. Did you add any oil? I’ll get you through this just bear with me. A/C is a specalty of mine.
yep maxing out at 112. Clutch seams to be engaging fine to me, belt tension is good. yes freon was the same from last year. no I did not put on a new dryer i bought one. but could not get the old one off with out twisting the week pipes connected to it. No I did not add oil. I was told the cans had oil in them. infact I was told I would be putting in to much oil, but they may be wrong.
I suspect I may be low on r134a but I dont wont to over fill since it’s slightly past where it should be on the low side.
Quoted From gaseousmercury:
What is the make of the car? What brand freon are you using? If you can post some pictures under the hood please do. I’m trying to determine if you have an expansion valve or an orifice tube and whether you have or or low pressure filtration. I can walk you through some trouble shooting step by step today send me an e-mail for time and I’ll post on forum; e-mail because I don’t always get forum updates forwarded to my e-mail. By the way what brand manifold and pump did you buy.
MY truck is a 1998 gmc k1500. I’m using advanced auto parts brand freon. The pump and gauge set were from harbor freight they got really good reviews.
that big mettle hose bolted to the compressor is new I had to replace the hole thing.Quoted From college man:
according to my pt chart for a 70 deg day. the high side should be approx 124 psi you were at 112 psi you are low on charge.
how are you calculating you charge?Thats what I’m thinking but since the low side is aleady slightly higher than it should be. I did not want to over fill it.
I have been PMing gaseousmercury back and forth he has been very help full.
He thinks the seals in my compressor is going because when i rev the engine to 2k the ac gets very cold and when it goes back to idle it gets warm again.
can any one confirm this. i dont want to through parts at it. especially expensive ones.
ok I think I found the problem. I was on another forum (yes I have been cheating on you guys… sorry) he suggested I check my orifice tube that goes in the condenser. Turns out. ITS MISSING!!! I had a new condenser put in a couple years ago by a shop I guess the guy forgot to put it in there.
Hopefully that is the problem. Thanks guys for your help.
lol I did not know that OrificeTube was a bad word.
Quoted From thepope:
ok I think I found the problem. I was on another forum (yes I have been cheating on you guys… sorry) he suggested I check my orifice tube that goes in the condenser. Turns out. ITS MISSING!!! I had a new condenser put in a couple years ago by a shop I guess the guy forgot to put it in there.
Hopefully that is the problem. Thanks guys for your help.
lol I did not know that OrificeTube was a bad word.
If the orificetube was missing, you wouldn’t have a change in pressure from high to low sides, as the restriction is there on purpose to create a pressure differential. If it was left out, you would just read the same pressure on both sides. I honestly am hesitant to provide advice on HVAC systems, because they really should be serviced by professionals, but the fact that the high side is reading low, and the low side is reading high, I would have to at least acknowledge that a failing compressor is a very real possibility. In fact, it it was my car or truck, I would probably check the orificetube for debris from a compressor coming apart. If that were the case, I would need to replace the compressor, the condensor, and probably the receiver/drier or accumulator for good measure, as chunks of the compressor will flow along the system and clog all these components up. But again, I’m just saying what I would do, because I think this system in particular should be handled by certified professionals. I mean no disrespect, but people don’t realize the damage refrigerant can do not only to the environment, but to the person handling it if they are unaware of what they are doing. Good luck man.
Edit: I checked a couple sites, and they suggested that some systems have more than one orificetube. I have never personally experience one, but I suppose if one were missing, this could cause your issue.
Is the compressor turning on and maxing out at 112? is the clutch engaging on the compressor? Hows the belt tension? Was there any freon left in the sysytem for last year. Did you put in a new dryer or accumulator; I’m not sure which is on that vehicle. Did you add any oil? I’ll get you through this just bear with me. A/C is a specalty of mine.
What is the make of the car? What brand freon are you using? If you can post some pictures under the hood please do. I’m trying to determine if you have an expansion valve or an orifice tube and whether you have or or low pressure filtration. I can walk you through some trouble shooting step by step today send me an e-mail for time and I’ll post on forum; e-mail because I don’t always get forum updates forwarded to my e-mail. By the way what brand manifold and pump did you buy.
according to my pt chart for a 70 deg day. the high side should be approx 124 psi you were at 112 psi you are low on charge.
how are you calculating you charge?If you had no metering device then you have flooded condition back to the compressor. which will destroy the compressor valves.
If you had no metering device installed. then your high side pressure would be the same as your low side. I don’t know who your
talking to or what your reading but. …….. … you may have a defective metering device. But based on what you have posted the system
is low on charge. good luck and keep us posted C8-)A++++++ on Beefys post
- You must be logged in to reply to this topic.