Complete AC recharge
Complete AC recharge
Okay, I just installed a new compressor (OE). I was told by a guy at the auto store that usually a new compressor already comes with enough pag oil inside so there is no need to put more oil in. Is this true? I'm going to vacuum that thing, is vacuuming going to take those oils out? Also, how many 12ozs cans of freon should I get? What's the capacity of our R134a system? 60oz? Should I install more oils, if yes, how many oz is needed?
The system takes 1.98 plus or minus .11 pounds of R-134a and up to 6.8 ounces of oil. So adding two pounds should be okay.
According to the FSM, there should be some oil coming out when evacuating the system and it should be recorded along with the amount that came out of the compressor drain hole. Then drain the oil of the new compressor to see how much more oil will be needed to be added into the system. Then put back the new oil along with the extra needed oil.
Also, just in case, read the compressor warranty. Some may claim that you will need to get a new dryer too or the warranty will be void if the compressor were to fail without replacing it.
According to the FSM, there should be some oil coming out when evacuating the system and it should be recorded along with the amount that came out of the compressor drain hole. Then drain the oil of the new compressor to see how much more oil will be needed to be added into the system. Then put back the new oil along with the extra needed oil.
Also, just in case, read the compressor warranty. Some may claim that you will need to get a new dryer too or the warranty will be void if the compressor were to fail without replacing it.
Might as well get a new dryer anyway. No reason not to for a ~$20 part. I replace the dryer any time I open an a/c system. You don't really "have" to unless the a/c system is open for a few days, but seeing as they're not much money, I always do anyway.
$40 for 92+ last I checked
yo yo I got these bad boys:


The blue line is connected to low pressure.
The red to high pressure
The yellow line goes to the pump. What I don't get is at the gauge set yellow line input is a T connector. I'm pretty sure one side goes to the pump, but what about the other side on that T? Does it need to be connected to anything? Also, the pump doesn't have an outlet to drop the receiving oil. Any idea where it could be going to?
Any ideas as to how I should I use this thing? I've never done this before so I want to learn this once.


The blue line is connected to low pressure.
The red to high pressure
The yellow line goes to the pump. What I don't get is at the gauge set yellow line input is a T connector. I'm pretty sure one side goes to the pump, but what about the other side on that T? Does it need to be connected to anything? Also, the pump doesn't have an outlet to drop the receiving oil. Any idea where it could be going to?
Any ideas as to how I should I use this thing? I've never done this before so I want to learn this once.
yo yo I got these bad boys:


The blue line is connected to low pressure.
The red to high pressure
The yellow line goes to the pump. What I don't get is at the gauge set yellow line input is a T connector. I'm pretty sure one side goes to the pump, but what about the other side on that T? Does it need to be connected to anything? Also, the pump doesn't have an outlet to drop the receiving oil. Any idea where it could be going to?
Any ideas as to how I should I use this thing? I've never done this before so I want to learn this once.


The blue line is connected to low pressure.
The red to high pressure
The yellow line goes to the pump. What I don't get is at the gauge set yellow line input is a T connector. I'm pretty sure one side goes to the pump, but what about the other side on that T? Does it need to be connected to anything? Also, the pump doesn't have an outlet to drop the receiving oil. Any idea where it could be going to?
Any ideas as to how I should I use this thing? I've never done this before so I want to learn this once.

The oil doesn't go into the pump, it goes directly into your A/C system. Not sure on the Maxima, but I know on my Civic I put a few oz. in the compressor itself, and then an oz or two in the condensor, and then usually an oz or two goes in the dryer.
Funny I have that exact gauge set and vacuum pump. The gauge set is pretty cheap, but the pump works well (even though it sounds a bit anemic).
You probably want to do some research on using the gauges. I'm no expert on using the gauges so I won't try to explain, too many variables.
Last edited by James92SE; May 24, 2010 at 04:37 PM.
Okay guys, I got it done. Took me an hour. I vacuumed the system for 35mins.
Result: 30 PSI (low) & 190 PSI (high). The compressor operates extremely quiet. I can't even tell when the clutch is engaged unless I put my ear right next to the compressor. Wow, nice nice.
New Parts Changed: Evaporator ($45), Compressor ($100), O-ring kit ($8), and Dryer ($17).
Regarding the capacity, it took me 2 cans of 12oz refrigerant ($13) and 1 can of 3oz oil ($4). I should've not press in that 3 oz of oil. What a waste of money, now I'm definitely sure my compressor was already fully loaded with PAG oil.
Refrigerant, Oil, AC Gauge Set, & 2.5cfm pump cost me $150 total. Not bad, I like the fact that I get to own the tools.
Result: 30 PSI (low) & 190 PSI (high). The compressor operates extremely quiet. I can't even tell when the clutch is engaged unless I put my ear right next to the compressor. Wow, nice nice.
New Parts Changed: Evaporator ($45), Compressor ($100), O-ring kit ($8), and Dryer ($17).
Regarding the capacity, it took me 2 cans of 12oz refrigerant ($13) and 1 can of 3oz oil ($4). I should've not press in that 3 oz of oil. What a waste of money, now I'm definitely sure my compressor was already fully loaded with PAG oil.
Refrigerant, Oil, AC Gauge Set, & 2.5cfm pump cost me $150 total. Not bad, I like the fact that I get to own the tools.
Last edited by bvtran; May 25, 2010 at 11:16 PM.
anyone knows what is that tard looking smelly crap that Nissan wrapped around the orifice that attached to the evaporator core? I didn't know where to get that item so when I changed my evap core, I just reuse it and man that thing is annoying as hell. When it gets a little too hot, it melts and produces road tardy odor. I swore, it stinks...is there a chemical out there that I can use to neutralize it?
It's called prestite tape (I think that may be a brand name?). It's meant to insulate the bulb portion of the expansion valve from the ambient air around it. That way, it measures the refrigerant temp as it leaves the evaporator rather than the air around it. Also, it keeps condensation from dripping down and soaking the floor/whatever
Odd that it's giving you such an odor. I've never had such a strong odor before, especially on stuff you've re-used. Why would it be getting so hot as to produce a tar-like smell? Did you heat it up to wrap/press it? Even if so, it shouldn't STAY smelling like tar after it cools off
Odd that it's giving you such an odor. I've never had such a strong odor before, especially on stuff you've re-used. Why would it be getting so hot as to produce a tar-like smell? Did you heat it up to wrap/press it? Even if so, it shouldn't STAY smelling like tar after it cools off
Not sure about other Nissan's though..
Actually, 3rd gens have pretty stout/long lasting/trouble free factory A/C systems. You really don't see many A/C complaints/problems among 3rd gens. I see 4th gen A/C threads ALL THE TIME. Nissan really went cheap with the 4th gen.
Not sure about other Nissan's though..
Not sure about other Nissan's though..
It's called prestite tape (I think that may be a brand name?). It's meant to insulate the bulb portion of the expansion valve from the ambient air around it. That way, it measures the refrigerant temp as it leaves the evaporator rather than the air around it. Also, it keeps condensation from dripping down and soaking the floor/whatever
Odd that it's giving you such an odor. I've never had such a strong odor before, especially on stuff you've re-used. Why would it be getting so hot as to produce a tar-like smell? Did you heat it up to wrap/press it? Even if so, it shouldn't STAY smelling like tar after it cools off
Odd that it's giving you such an odor. I've never had such a strong odor before, especially on stuff you've re-used. Why would it be getting so hot as to produce a tar-like smell? Did you heat it up to wrap/press it? Even if so, it shouldn't STAY smelling like tar after it cools off

Retrofitting an r12 system to r134a isn't really an upgrade. A retrofitted system generally doesn't even work as well, let alone better. Although, depending on the car/condenser design, it can work well enough that you don't notice a large dropoff in cooling ability. Just FYI
Retrofitting an r12 system to r134a isn't really an upgrade. A retrofitted system generally doesn't even work as well, let alone better. Although, depending on the car/condenser design, it can work well enough that you don't notice a large dropoff in cooling ability. Just FYI
Actually, 3rd gens have pretty stout/long lasting/trouble free factory A/C systems. You really don't see many A/C complaints/problems among 3rd gens. I see 4th gen A/C threads ALL THE TIME. Nissan really went cheap with the 4th gen.
Not sure about other Nissan's though..
Not sure about other Nissan's though..
Actually, 3rd gens have pretty stout/long lasting/trouble free factory A/C systems. You really don't see many A/C complaints/problems among 3rd gens. I see 4th gen A/C threads ALL THE TIME. Nissan really went cheap with the 4th gen.
Not sure about other Nissan's though..
Not sure about other Nissan's though..
My 3rd gen I had to replace the condenser before I could get cold air and currently isn't working because of a wrong size o-ring that couldn't hold pressure by the condenser, otherwise I'd say they both do have great A/C systems
On my max, the bolt holding the low pressure hose to the compressor was rusted as well on the inner thread of the compressor which caused a very large leak. Instead of fixing it, I might as well convert everything from R-12 to R-134a. Got used evaporator compressor, condenser, lines and hoses from a donor 94. So far it's working well and it's operating much quieter than the setup it had.
On my max, the bolt holding the low pressure hose to the compressor was rusted as well on the inner thread of the compressor which caused a very large leak. Instead of fixing it, I might as well convert everything from R-12 to R-134a. Got used evaporator compressor, condenser, lines and hoses from a donor 94. So far it's working well and it's operating much quieter than the setup it had.
Some body replied to my post on the topic of putting r134a into r12 system and suggested this freeze 12 stuff that is the same thing as r12. It read that it would work with my r12 system the same.
Freeze 12 is actually 80%+ r134a.. The rest is 142b which supposedly helps carry the mineral oil through the system to lubricate it (r134a won't)..
From what I understand, it doesn't work nearly as well as r12, and probably not even as well as a properly retrofitted r134a conversion. Most experts I've seen on some A/C forums really don't recommend it
From what I understand, it doesn't work nearly as well as r12, and probably not even as well as a properly retrofitted r134a conversion. Most experts I've seen on some A/C forums really don't recommend it
bvtran... what kind of center vent temps are you getting at idle with the r134a (as well as the outside temp at the time)?
I generally despise r134a but it seems the 3rd gen has a stout enough system to handle the conversion well. My "new" '92 keeps losing its charge so I'm contemplating which direction I want to go with it. My '89 Civic has such a rinky dink little A/C system that I was getting 70+ center vent temps when I retrofitted it to r134a, hence my move back to r12.
I generally despise r134a but it seems the 3rd gen has a stout enough system to handle the conversion well. My "new" '92 keeps losing its charge so I'm contemplating which direction I want to go with it. My '89 Civic has such a rinky dink little A/C system that I was getting 70+ center vent temps when I retrofitted it to r134a, hence my move back to r12.
bvtran... what kind of center vent temps are you getting at idle with the r134a (as well as the outside temp at the time)?
I generally despise r134a but it seems the 3rd gen has a stout enough system to handle the conversion well. My "new" '92 keeps losing its charge so I'm contemplating which direction I want to go with it. My '89 Civic has such a rinky dink little A/C system that I was getting 70+ center vent temps when I retrofitted it to r134a, hence my move back to r12.
I generally despise r134a but it seems the 3rd gen has a stout enough system to handle the conversion well. My "new" '92 keeps losing its charge so I'm contemplating which direction I want to go with it. My '89 Civic has such a rinky dink little A/C system that I was getting 70+ center vent temps when I retrofitted it to r134a, hence my move back to r12.
I remember when I first got my 3rd gens A/C working, I was getting like 24-30 degrees Fahrenheit with about 80-85 ambient temp, 'twas awesome. My 4th gen's isn't as freezing cold but enough to make you open the window a bit or lower the AC
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. But it includes the dual pressure switch which I intended to replace too. Not sure if it's included on aftermarket dryers.
