# A/C line filter.



## Dyno58 (Apr 7, 2007)

1996 Nissan Sentra A/C 

I had the a/c recharged and the pressure on the high side a/c line was very high. They told me the orifice tube might be clogged. I did a little research and found out the 1996 Nissan Sentra does not have a orifice tube. Is there any type of filter with in the a/c lines. Please help. Thanks


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## IanH (Feb 11, 2003)

Dyno58 said:


> 1996 Nissan Sentra A/C
> 
> I had the a/c recharged and the pressure on the high side a/c line was very high. They told me the orifice tube might be clogged. I did a little research and found out the 1996 Nissan Sentra does not have a orifice tube. Is there any type of filter with in the a/c lines. Please help. Thanks


What is the low side pressure ? at what rpm.
What do you call high ?
Maybe just overcharged.


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## Dyno58 (Apr 7, 2007)

There are two lines that go into the firewall for the ac. One is labeled H and the other is labeled L for low. I had my A/C recharged and the meter that was attached to the a/c lines for the freon read very high. They told me that there is some kind of obstruction in the line. From what I understand the lines have some kind of filtration system that pick up small particles of metal that might come from the compressor. Most cars have what is called an orifice tube. It's a small tube that has mesh screens. I have read that Nissan Sentra's do not have orifice tubes. I was wondering if anyone knows what kind of filtration system it uses and where it's located. Thanks.


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## IanH (Feb 11, 2003)

Dyno58 said:


> There are two lines that go into the firewall for the ac. One is labeled H and the other is labeled L for low. I had my A/C recharged and the meter that was attached to the a/c lines for the freon read very high. They told me that there is some kind of obstruction in the line. From what I understand the lines have some kind of filtration system that pick up small particles of metal that might come from the compressor. Most cars have what is called an orifice tube. It's a small tube that has mesh screens. I have read that Nissan Sentra's do not have orifice tubes. I was wondering if anyone knows what kind of filtration system it uses and where it's located. Thanks.


At the top of the B14 forum there is a Factory Service manual (FSM) for download.
http://www.nissanforums.com/b14-95-99-chassis/60760-b14-full-service-manual.html
I suggest you download this and look at HA11, it shows an expansion valve and a receiver dryer Nissan calls a liquid tank. Both of these may have a filter screen, I do not know in this case. Maybe the FSM will tell you.
My pressures run high, our condenser is small, others from AZ and TX have complained about this, fitting bigger fans is a partial answer. Also my Freon level is too high. 
What are your readings ? does the A/c cycle on the low cut off switch or the high pressure switch?


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## Dyno58 (Apr 7, 2007)

It cycles on the high pressure switch. My readings are 250 and 300+ under load. Does this sound normal? Thanks for the info you have given me so far.


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## IanH (Feb 11, 2003)

Dyno58 said:


> It cycles on the high pressure switch. My readings are 250 and 300+ under load. Does this sound normal? Thanks for the info you have given me so far.


Ok, so does mine, for at least a year or two !!
SO if it works OK I would not worry to much.
My pressures are higher than yours, so probably my hi side switch is just set a bit higher.
I am planning to work on mine when it gets a bit hotter. 
First step is to lower the freon level.


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## Dyno58 (Apr 7, 2007)

I'm going to work on mine this weekend and replace some parts. I will tell you how it goes.


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## wrench (Jan 31, 2007)

FYI Dyno58, my A/C instructor (a FEW years ago) stated that 90+% of A/C problems are due to the receiver/drier. They are supposed to be replaced every two years but nobody ever does it that often due to cost.
The receiver/drier (liquid tank) in your car is the filter you're asking about.
Also, expansion valves can and do stick over time. If your going to evacuate the system, and its affordable, you might consider replacing that also. GL


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## Dyno58 (Apr 7, 2007)

Thanks for the info. How much is the receiver/drier? How difficult is it to change?


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## wrench (Jan 31, 2007)

Dyno...just call a shop and get a quote. In my day they ran about $100 (P&L). The reason I mention a shop is because you need to have a freon recovery machine that also has a vacuum pump. The vacuum pump is REQUIRED to properly suck the system down and remove ALL moisture from the system. Flushing the system is also a worthwhile cost.
However, ultimately its up to you as to what is done.


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