1993 Nissian Sentra A/C not cooling

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  #1  
Old 07-28-06, 02:43 PM
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Unhappy 1993 Nissan Sentra A/C not cooling

Hey, I have a 1993 Nissan senta (140, 000 miles), the a/c is blowing hot air. My father has been working on it when he has time. He converted the air conditioning unit over from 12A to 134A freon. It was blowing good for acouple months, but then it started making a high pitch noice from the compressor when the a/c switch was turned on. Also it would not cool when when vehcile was not in motion (only when moving). Now is only blowing hot air and compressor is still working, but making that high annoying noice. What is wrong? Have any idea what needs to be changed and cost? Do not have tons of money to take to auto air condtioning specialist. Where the valve/switch is on the a/c system under the hood?

It is just way too hot in the south not to have air conditioning!!

Any help will be appreciated!!!
 

Last edited by nissianck; 07-28-06 at 08:04 PM. Reason: take off word coloring
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  #2  
Old 07-28-06, 07:27 PM
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I would say that the new coolant did not have enough lubrication for the condenser and burned it up. I would try changing back to the old coolant if you can find some and/or switch out the condenser for one off of a newer car.
 
  #3  
Old 07-28-06, 07:45 PM
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nissan a/c

first, please, do away with the colored stuff in the postings, most of us are older than dirt and find it hard to read most anything any ways, thank you. as far as your nissan is concerned,,well,it don't look too good, first thing is that shoulda been done is why it lost it's ability to cool in the first place, too many people went to the
"retrofit" r134-a to get a/c in their cars to try and patch a problem that needs more work done than a simple charge of freon.
the only suggestion i could give would be to have the car looked at by a pro, there are way too many things that a doityourselfer
can't do, especially with anything to do with a/c systems.
i hate to end it on a note like this, but that is the best route
for you to get it up and running. let us know how it goes.

barry
 
  #4  
Old 07-29-06, 03:43 AM
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Originally Posted by nissianck
Hey, I have a 1993 Nissan senta (140, 000 miles), the a/c is blowing hot air. My father has been working on it when he has time. He converted the air conditioning unit over from 12A to 134A freon. It was blowing good for acouple months, but then it started making a high pitch noice from the compressor when the a/c switch was turned on. Also it would not cool when when vehcile was not in motion (only when moving). Now is only blowing hot air and compressor is still working, but making that high annoying noice. What is wrong? Have any idea what needs to be changed and cost? Do not have tons of money to take to auto air condtioning specialist. Where the valve/switch is on the a/c system under the hood?

It is just way too hot in the south not to have air conditioning!!

Any help will be appreciated!!!
nissianck,
You said your father converted it from R-12 to R-134a. Can you describe in detail what he did? Did he use a department store kit? Did he flush the system? Did he check for; and fix any leaks? Did he pull a deep vacuum before charging? Did he monitor (both) the high side and the low side, as well as monitor the ambient outdoor temperature while charging? These are just a few questions we'd need answers to in order to figure out what went wrong!

There's no way on earth anybody could tell you how to repair you A/C without some basic information about the system. But, even though you've only provided a very small amount of information, to me, this seems like the classic "Do It Yourself" A/C job gone sorely wrong!

When it comes to A/C work, there are no shortcuts and no room for errors. You must get it right the first time! ! ! ! !
Phil
 
  #5  
Old 07-29-06, 08:14 PM
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Arrow More info and details

Originally Posted by Philossifer
nissianck,
You said your father converted it from R-12 to R-134a. Can you describe in detail what he did? Did he use a department store kit? Did he flush the system? Did he check for; and fix any leaks? Did he pull a deep vacuum before charging? Did he monitor (both) the high side and the low side, as well as monitor the ambient outdoor temperature while charging? These are just a few questions we'd need answers to in order to figure out what went wrong!

There's no way on earth anybody could tell you how to repair you A/C without some basic information about the system. But, even though you've only provided a very small amount of information, to me, this seems like the classic "Do It Yourself" A/C job gone sorely wrong!

When it comes to A/C work, there are no shortcuts and no room for errors. You must get it right the first time! ! ! ! !
Phil
Well, somehow everything I just typed got deleted. He did not use a store kit. The kit consisted of: 2 or 3 cans of 134 freon, 1 can of oil, freon temperature gauge,a vacuum, and air compressor. He used the air compressor to blow out the hoses, compressor, and accumulator/filter drier (which was full of oil). He also vaccumed out the hoses and all the system. He did montior the low side while charging, but could not get to the high side. He checked for leaks and there was none to fix.At the time he said the tempatures were at where they were suppost to be. Ok, this is when it was cooling, but then started making the annoying high pitch noice from the compressor after a few months. When he put the gauge on it recently it read 80 to 100 on low side while charging(which is suppost to be 45). The temperature at the time was not high (around 60's or 70's) it was in the morning in a garage with decent ventlation. The first time he when he changed the freon to 134. Could it be the compressor and/or condenser is not working correctly and/or the evaporator and/or the expansion valve? Also he could not find the expansion valve on the orfifce tube, any idea where it could be?

Are you an auto air condtioning techinian or a do it yourself mechanic? What steps may have been skipped? Any suggestions or knowledge of what needs to be replaced or how to do it correctly without going to shop?Thanks!!!
 
  #6  
Old 07-29-06, 09:14 PM
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It sounds like your compressor may be history and I think that is one of the DVK14Ds very expensive. If the compressor has grenaded you really need professional help and unfortunately you are looking at around 1500 bones which is probably about what your vehicle is worth. Before taking further action have the low and high pressures taken at idle and then at 1500 rpm it is possible that maybe the clutch on the compressor could be producing the noise and not turning the compressor shaft (doubt it) or you could have a system restriction (these use the TXV valves) maybe at the expansion device or filter drier. If it turns out to be the clutch you may be able to swap it out without removing the compressor or refrigerant charge Good Luck
 
  #7  
Old 07-29-06, 09:39 PM
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my father says...

Originally Posted by Tsubaki
It sounds like your compressor may be history and I think that is one of the DVK14Ds very expensive. If the compressor has grenaded you really need professional help and unfortunately you are looking at around 1500 bones which is probably about what your vehicle is worth. Before taking further action have the low and high pressures taken at idle and then at 1500 rpm it is possible that maybe the clutch on the compressor could be producing the noise and not turning the compressor shaft (doubt it) or you could have a system restriction (these use the TXV valves) maybe at the expansion device or filter drier. If it turns out to be the clutch you may be able to swap it out without removing the compressor or refrigerant charge Good Luck
He thinks it not the clutch, it is turning just fine. It could be the some restrictions in the system. You think the filter drier and expansion valve need to replaced? Also will get the low and high pressures tested soon at idle and high rpm and will get back you. Thanks!!
 
  #8  
Old 07-30-06, 05:39 AM
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Originally Posted by nissianck
Well, somehow everything I just typed got deleted. He did not use a store kit. The kit consisted of: 2 or 3 cans of 134 freon, 1 can of oil, freon temperature gauge,a vacuum, and air compressor. He used the air compressor to blow out the hoses, compressor, and accumulator/filter drier (which was full of oil). He also vaccumed out the hoses and all the system. He did montior the low side while charging, but could not get to the high side. He checked for leaks and there was none to fix.At the time he said the tempatures were at where they were suppost to be. Ok, this is when it was cooling, but then started making the annoying high pitch noice from the compressor after a few months. When he put the gauge on it recently it read 80 to 100 on low side while charging(which is suppost to be 45). The temperature at the time was not high (around 60's or 70's) it was in the morning in a garage with decent ventlation. The first time he when he changed the freon to 134. Could it be the compressor and/or condenser is not working correctly and/or the evaporator and/or the expansion valve? Also he could not find the expansion valve on the orfifce tube, any idea where it could be?

Are you an auto air condtioning techinian or a do it yourself mechanic? What steps may have been skipped? Any suggestions or knowledge of what needs to be replaced or how to do it correctly without going to shop?Thanks!!!
nissianck,
I'm not an automotive mechanic, I work on refrigeration systems. Car A/C systems are just like refrigeration only not as complicated. I have a 609 certification as well as the 608 certification which covers small appliances, low pressure systems and high pressure systems. Also, I have a 2-year certificate in "Climate Control Technology" from the local community college. So I know a little bit about this subject!

After reading your post, I can tell you one MAJOR mistake your father made which probably caused your failure.

You said he blew compressed air through the accumulator. That is the kiss of death for an A/C system. First of all, technically, the accumulator should be replaced any time the system is opened for anything other than changing an o-ring or other minor repair. When you add a new component to the system like a compressor or condenser or do a retrofit from R-12 to R-134a you MUST install a new accumulator. No if’s and’s or but’s about it.

The accumulator has a desiccant bag in it to absorb moisture in the system during normal operation. When your dad blew compressed air into the accumulator he saturated the desiccant with moisture or, even worse than that, the pressure from the compressed air damaged the desiccant bag and when the system started running, the desiccant got distributed throughout the system. The desiccant is like sand and when it finds its way to the compressor....that compressor will be history real fast. But even worse, now, all that sandy material is spewed throughout your whole A/C system and it will have to be flushed. If you just install a new compressor without flushing the system, I promise, that compressor will fail too!

The evaporator can be flushed and the condenser can be flushed too, but to be honest, you're probably better off with a new condenser. It's really hard to get all the crud out of a condenser after a compressor self-destructs! All the hoses can be flushed. DO NOT FLUSH the accumulator, and if your system has a muffler, do not flush that either. You will have to replace the expansion valve and the accumulator and you might as well replace all the o-rings since the system is all apart anyway.

It sounds like your compressor is toast because you’re getting such a high suction pressure. The fact that the low side is not pulling down pretty much tells you the compressor is done! So, now you need a new compressor too.

At this point, if you’re gonna’ do all the work yourself (or your dad) get ready to dump a grand or more into you’re A/C system. If you take it to a shop, the price will be much higher that.

I’m sorry to say but it sounds like your dad made some very big mistakes and now it’s going to cost you a lot of money to correct them!
Good luck,
Phil
 
  #9  
Old 07-30-06, 05:52 AM
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Originally Posted by nissianck

Ok, this is when it was cooling, but then started making the annoying high pitch noice from the compressor after a few months.

When he put the gauge on it recently it read 80 to 100 on low side while charging(which is suppost to be 45). The temperature at the time was not high (around 60's or 70's) it was in the morning in a garage with decent ventlation.

The high pressure reading on low side indicates that the A/C compressor is off, this could be number of things that causing it like low/no freeon in the system and or electrical problem, no power feed to air compressor when turned on and or because of lack of freeon, the a/c pressure switch is stay open which = no power to compressor.

The other high pitch noise coming from compressor could be easy as loose belt or could be bad compressor itself, when you said " it's not the clutch and it's spinning", which part does he mentioned to?, the inner/center part of the compressor(clutch) or the part that the belt rides on(pulley)?.
 
  #10  
Old 07-30-06, 10:49 AM
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Exclamation flush the system?

Originally Posted by Philossifer
nissianck,
I'm not an automotive mechanic, I work on refrigeration systems. Car A/C systems are just like refrigeration only not as complicated. I have a 609 certification as well as the 608 certification which covers small appliances, low pressure systems and high pressure systems. Also, I have a 2-year certificate in "Climate Control Technology" from the local community college. So I know a little bit about this subject!

After reading your post, I can tell you one MAJOR mistake your father made which probably caused your failure.

You said he blew compressed air through the accumulator. That is the kiss of death for an A/C system. First of all, technically, the accumulator should be replaced any time the system is opened for anything other than changing an o-ring or other minor repair. When you add a new component to the system like a compressor or condenser or do a retrofit from R-12 to R-134a you MUST install a new accumulator. No ifís andís or butís about it.

The accumulator has a desiccant bag in it to absorb moisture in the system during normal operation. When your dad blew compressed air into the accumulator he saturated the desiccant with moisture or, even worse than that, the pressure from the compressed air damaged the desiccant bag and when the system started running, the desiccant got distributed throughout the system. The desiccant is like sand and when it finds its way to the compressor....that compressor will be history real fast. But even worse, now, all that sandy material is spewed throughout your whole A/C system and it will have to be flushed. If you just install a new compressor without flushing the system, I promise, that compressor will fail too!

The evaporator can be flushed and the condenser can be flushed too, but to be honest, you're probably better off with a new condenser. It's really hard to get all the crud out of a condenser after a compressor self-destructs! All the hoses can be flushed. DO NOT FLUSH the accumulator, and if your system has a muffler, do not flush that either. You will have to replace the expansion valve and the accumulator and you might as well replace all the o-rings since the system is all apart anyway.

It sounds like your compressor is toast because youíre getting such a high suction pressure. The fact that the low side is not pulling down pretty much tells you the compressor is done! So, now you need a new compressor too.

At this point, if youíre gonnaí do all the work yourself (or your dad) get ready to dump a grand or more into youíre A/C system. If you take it to a shop, the price will be much higher that.

Iím sorry to say but it sounds like your dad made some very big mistakes and now itís going to cost you a lot of money to correct them!
Good luck,
Phil
Alright, when you say "flush the system" what do you mean? What do you flush the system with? IF need to go to a shop to do, cost?OK, so need a new compressor, accumlator and expansion valve. Having problem finding expansion valve on orfifce tube? The compressor was proabably already going bad anyways when he decided to change to 134 refrigent. I the know the accumlator and expansion valves are not expensive as the compressor and condenser.Thanks for all your input!!

Also when dad took out freon, a black gubby substance came out looked like oil, but dad did not add much oil to the line when added freon this last time recently. Have any idea what the black oily substance is was not a gas like usaully? It probably the comdemnation?
 

Last edited by nissianck; 07-30-06 at 11:33 AM. Reason: black guppy substance??
  #11  
Old 07-30-06, 11:39 AM
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Originally Posted by nissianck
Alright, when you say "flush the system" what do you mean?
I mean take every fitting apart and flush a solvent through each component individually until the solvent comes out clear.
What do you flush the system with?
You can buy an A/C approved solvent at any auto parts store. There are other solvents you could use but I wouldn't recommend them for the home DIY'er
IF need to go to a shop to do, cost?
Just a guess here: Anywhere from under $50 all the way up to $2500 depending on how much damage there is, how many components need to be replaced.
OK, so need a new compressor, accumulator and expansion valve. Having problem finding expansion valve on orifice tube? The compressor was probably already going bad anyways when he decided to change to 134 refrigent.
Mistake No. 2: If the compressor was going bad, then you should NOT have converted to R-134a without replacing the compressor. R-134a runs at a higher pressure than R-12 and those higher pressures will quickly kill a weak compressor and contaminate the whole system with crud from the compressor.
I the know the accumulator and expansion valves are not expensive as the compressor and condenser. Thanks for all your input!!
Some expansion valves can be expensive....O-tube's are generally pretty cheap unless you go with a VOV O-tube. (variable orifice valve)
Good luck,
Phil
 
  #12  
Old 07-30-06, 07:07 PM
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Originally Posted by Philossifer
I mean take every fitting apart and flush a solvent through each component individually until the solvent comes out clear.

You can buy an A/C approved solvent at any auto parts store. There are other solvents you could use but I wouldn't recommend them for the home DIY'er

Just a guess here: Anywhere from under $50 all the way up to $2500 depending on how much damage there is, how many components need to be replaced.

Mistake No. 2: If the compressor was going bad, then you should NOT have converted to R-134a without replacing the compressor. R-134a runs at a higher pressure than R-12 and those higher pressures will quickly kill a weak compressor and contaminate the whole system with crud from the compressor.

Some expansion valves can be expensive....O-tube's are generally pretty cheap unless you go with a VOV O-tube. (variable orifice valve)
Good luck,
Phil
Thanks for all the help ....tell you more when if thing get fixed later...
 
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