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-   -   I can't get R134a to flow into my 2001 Frontier (http://www.infamousnissan.com/forum/showthread.php?t=46468)

Scott in TX 05-14-2022 05:08 PM

I can't get R134a to flow into my 2001 Frontier
 
It's my first time repairing an auto A/C. It's a 2001 Frontier 2.4L. I put in a re-manufactured compressor, new condenser, new drier and expansion valve, and also flushed the evaporator and all lines.

I set up vacuum and gauges, ran the pump an hour, left gauges on for another hour to check for leakage, then closed the high side manifold valve. I expected most of the can to go into the high side, but less than an ounce went in (I weighed the can before and after). It is mid May in South Texas, so around 95 degrees and 86% humidity.

I closed the high side valve, started the engine, jumped the compressor relay socket to get the compressor going, turned the A/C dial and fan to high, and then tried to add refrigerant to low side. I kept at it for 20 min., but only about 1-2 ounces went in.

Why isn't the refrigerant going in? How long should it take to get the first can of refrigerant into the low side of an empty system with compressor running???

The yellow hose with the gauge-and-hose set I borrowed has a recessed valve threaded into one end (looks like a Schrader-type valve). Is that the end of the hose that should be threaded into the manifold? What's the purpose of that valve? I took that valve out the last time I tried to add refrigerant.

I'd appreciate some pointers, thanks!

cadillacdude1975 05-15-2022 03:05 AM

Does the can have that hole in the top? If it does, the can adapters that pierce the can will not let it flow. And you should not run the compressor with zero refrigerant. When you fill the system, turn the AC to max. As it starts filling, the compressor will engage once it has the minimum amount that triggers the low pressure switch.

Scott in TX 05-15-2022 03:40 AM

Quote:

Originally Posted by cadillacdude1975 (Post 559928)
Does the can have that hole in the top? If it does, the can adapters that pierce the can will not let it flow. And you should not run the compressor with zero refrigerant. When you fill the system, turn the AC to max. As it starts filling, the compressor will engage once it has the minimum amount that triggers the low pressure switch.


I got the cans with built-in-valves that shut when you take the fitting off. I know it's not good to run the compressor with no refrigerant, but I thought the compressor needed to be running in order for the refrigerant to flow in, because nothing was flowing in while the engine was off, to either the low or high side.


I had the manifold valves full-open, but I read that the sweet spot for maximum flow is somewhere halfway open... I'll try that next time.

Cusser 05-15-2022 02:21 PM

Quote:

Originally Posted by Scott in TX (Post 559916)
It's my first time repairing an auto A/C.

Well, not my first rodeo with same Frontier with 2.4 engines.

With my 1998 and 2004 Frontiers, I have replaced a high side line and removed an AC clutch shim (on the 1998) and installed a new compressor/condenser/drier (on my 2004).


Quote:

Originally Posted by Scott in TX (Post 559916)
I set up vacuum and gauges, ran the pump an hour, left gauges on for another hour to check for leakage, then closed the high side manifold valve.

This part is good.


Quote:

Originally Posted by Scott in TX (Post 559916)
I closed the high side valve, started the engine, jumped the compressor relay socket to get the compressor going

This is NOT a good thing to do; the compressor would be turning without any refrigerant in it !!!

This is what I do. I pull a good vacuum, like for 45 minutes. I turn the valves to isolate the vacuum pump and check for loss of vacuum for at least 15 minutes. Then I attach my can of R134a, and attach to the AC gauge set, and then vent any air out of the line using the R134a. Then I open the valve or valves to let the vacuum suck in most of the R134a from the can the can should get very cold, and OK to turn the can upside down during this stage.

Once the can stops being cold or lighter in weight, ONLY THEN does one start the engine and turn the AC on to complete the fill process. The valves get closed during switch to subsequent can so no outside air gets into the line. If one gets 11 oz. R134a out of a can, that would be considered good.

Disclaimers:
1. I have not yet had to deal with R134a cans with the government-required sealing valve and its adapter, have not heard great things about these. I might suggest to get a can side tap instead.

2. The fittings that go onto the schraeder service valves on the truck must be open, and must press the schraeder down to allow refrigerant to enter.

3. NEVER, EVER add and sealer or any refrigerant containing sealer, that can clog stuff PERMANENTLY and RUIN the system. Notice the CAPITAL LETTERS.

Scott in TX 05-15-2022 03:43 PM

Should there be a schraeder valve inside the yellow hose female fitting? What purpose does it serve? I took it out because I thought it might be part of the problem. Also, I thought it was OK to get some of the refrigerant into the high side (but not the low side) before starting the engine.

cadillacdude1975 05-16-2022 12:23 PM

The self sealing cans are a pain. The side tap is way better.

Cusser 05-16-2022 01:55 PM

Quote:

Originally Posted by Scott in TX (Post 559938)
Also, I thought it was OK to get some of the refrigerant into the high side (but not the low side) before starting the engine.

Before starting the engine, when just letting system vacuum pull in refrigerant, you can add through either high side or low side or both.


It wouldn't hurt to turn the compressor drive plate a couple of revolutions clockwise with a wrench before starting the engine, like one would do after adding oil to an open compressor.

Scott in TX 05-21-2022 10:55 PM

Tried again to charge the system today. Soon after the compressor began compressing, I heard the refrigerant blowing out of both compressor fittings. Does that sound like too much or too little torque, or what?


I'd put new O-rings on both fittings, and smeared them with PAG oil. Then in the bag of O-rings, I noticed there were two stamped sheet-metal washers (see photo) that are shaped like the compressor fittings. I didn't see anything like that when I took the lines off of the old compressor. Should those be used on a 2001 Frontier? If so, which way is up? Any additional rings needed? https://imgur.com/ykfWrzr


So I removed the fittings, put new O-rings on, re-installed the fittings, vacuumed it, then began charging with refrigerant... then heard it coming out of the compressor fittings AGAIN... I used the fattest O-ring in the assortment (Four Seasons) that fit onto the notch on the fittings. Should there also be an O-ring down in recesses on the compressor? Seems like I need some high-temp RTV to seal the fittings. I'm stumped.



https://imgur.com/xD5Pcdm
https://imgur.com/ykfWrzr

cadillacdude1975 05-22-2022 05:26 AM

The orings have to fit inside the compressor. They sit inside the channel. Once the line is inserted and torqued, the oring swells from the pressure and seals the connection. If it was leaking when you tried to fill it, it would have been sucking air the entire time the vacuum pump was running.

Cusser 05-22-2022 02:42 PM

Quote:

Originally Posted by Scott in TX (Post 560063)
Tried again to charge the system today. Soon after the compressor began compressing, I heard the refrigerant blowing out of both compressor fittings. Does that sound like too much or too little torque, or what?

I'd put new O-rings on both fittings, and smeared them with PAG oil. Then in the bag of O-rings, I noticed there were two stamped sheet-metal washers (see photo) that are shaped like the compressor fittings. I didn't see anything like that when I took the lines off of the old compressor. Should those be used on a 2001 Frontier? If so, which way is up? Any additional rings needed? https://imgur.com/ykfWrzr

So I removed the fittings, put new O-rings on, re-installed the fittings, vacuumed it, then began charging with refrigerant... then heard it coming out of the compressor fittings AGAIN... I used the fattest O-ring in the assortment (Four Seasons) that fit onto the notch on the fittings. Should there also be an O-ring down in recesses on the compressor? Seems like I need some high-temp RTV to seal the fittings. I'm stumped.
https://imgur.com/xD5Pcdm
https://imgur.com/ykfWrzr

https://imgur.com/xD5Pcdm
https://imgur.com/ykfWrzr

No RTV !!!


I am unable to see your linked Imgur photos. Below is a photo of my 1998 Frontier factory high pressure line (pinhole leak in the rubber hose) with its original factory O-ring and my replacement high pressure line with a brand-new O-ring (note that the new high pressure line fitting had to be shortened to match and seat, but that's whole different issue). So the lines' fittings need to be seated fully for the new-O-ring to seal. Pag oil or Nylog is good to lube them with.



https://www.thesamba.com/vw/gallery/pix/1663698.jpg


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