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Discussion Starter #1
My AC is back to acting weird. It cools after 15 or 20 mins of driving and sometimes cools for a whole trip but mostly drops to 60 and then goes back up to 70-80 and then just keeps cycling temps back and forth.

It kicks the idle control up and down, so that is working. The compressor clutch cycles on and off, engaging the compressor. It clicks very loudly when cycling on and off.

The dryer has a sensor on top that is what is killing the AC. That sensor snaps and the AC compressor kicks off and than once the AC kicks back in, the sensor snaps after some seconds and the compressor clutch disengages again.

What is that sensor? What would make it keep snapping closed or open and disengaging the compressor clutch?

At work, I will attempt to download the factory manual from that other site linked here and work my way through it but I just wanted to see what you guys think is kicking that on and off?

It's got fresh r134 and the vacuum held
 

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Discussion Starter #3
same thing before. that's what caused the vacuum and refill.

I don't know exactly how much 134, right around 38-40 ounces. the oil didn't all come out so I only put half of one of those little cans of in.

but its exactly the same as before, but it actually goes down to 60 instead of only going down to 70 and then back up.
 

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2004 Nissan Frontier XE KC KA24DE
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What's the r134 capacity for your truck? 38 -40 oz seems a bit much.

The r134 capacity for my truck is
0.65 kg +- 0.05 kg.

Which is = 650 grams and with the +- = 700 grams.

Each 12 oz can is 340 grams.
So two 12 oz (24 oz total) would be a perfect charge at 680 grams....falling between the 650g - 700g capacity.
 

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The sensor you speak of is a triple pressure switch.

Triple Pressure Switch (VG33E and VG33ER Models) NEHA0069S0301 The refrigerant system is protected against excessively high or low pressure. The protection is effected by either a dual pressure switch or a triple pressure switch located on the liquid tank. If the pressure falls out of specifications, the switch opens to interrupt compressor operation.
 

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Just a year ago I had an intermittent AC issue on my 1998 Nissan Frontier, at about 255K miles. AC would just stop blowing cold, then after a few minutes would work again. Since I have on this vehicle a dash indicator light I wired in parallel to the compressor wire, I knew that the AC clutch was getting positive voltage. So a couple of days later when the AC stopped blowing cold but the light was still on, I immediately pulled over and visually verified that the AC clutch was disengaged, even though it was getting power.

So I used a seized compressor from my 2004 Frontier to practice on, and figured out on that one that three 5mm bolts could be screwed into already-threaded holes to pull the clutch plate off. So I did this on my Frontier's compressor; I removed one thin shim, and put it back together, and it has worked fine since. I didn't need to unbolt the compressor or even remove or loosen the AC belt to do this.

Needing to remove an AC clutch shim to adjust for a worn AC clutch is a well-known and legitimate repair. This is called "decreasing the AC clutch gap".
 

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Discussion Starter #10
I knew I read that somewhere. I just couldn't recall the specifics on it. That will be good to check once I get the triple sensor to stop clicking (get the fluids into spec)
 

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I knew I read that somewhere. I just couldn't recall the specifics on it. That will be good to check once I get the triple sensor to stop clicking (get the fluids into spec)
All you have to do is measure the gap between clutch disc and pulley. Specs are in the FSM.
 

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I Think You're Problem is That You've Overfilled The System.

In the chart above it says our sytsem takes roughly 1.5 lbs. Each regular sized can is 12oz by weight. So a completely empty system will take 2.5 cans.

Did you rent a Vacuum Pump and Gauge Set from the Auto Parts Store? You may have over charged that system. Before i knew how to read those gauges i overcharged the system and it wouldn't blow cold. I just didn't know how to read the gauges and couldn't figure out why it wasn't blowing cold and i was only putting in like 2.5-3cans. Those Gauges different than the cheapo gauge you get for a top off. They're more accurate and detailed. My friend who does home AC came over and showed me how to read the guages. Since then i've fixed a handful of AC's. A couple weeks ago I swapped a compressor, condenser, and some O-Rings in my Maxima. The system only took less than 1.5 Cans or about 18 oz's total. I couldn't believe it. I just quit filling it when the temp at the coil hit around 35 or less. I wasn't going to argue with it. AC blows cold now. I get 39 at the vent!

On the blue Low Side Gauge it shows a temperature and that temperature is the temp at the Coil or Evaporator under the dash. Get your pressure to whatever it needs to be for that temp at the Coil to read around 35 degrees. If you can get it lower then all the better.

If you've over filled then let some pressure out til the temp drops to 35ish or if you're adding then add refrigerant till the temp hits 35ish. Thats pretty much the main thing i look at when doing a system fill. I vacuum to see if it holds and then slowly add refrigerant til i get to 35 degrees at the coil.


317982
 

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I also think that you've significantly overfilled the R134a. In post #28 here 2004 Frontier King Cab thread I added 25 oz. R134 when I re-did the AC compressor on my 2004 Frontier.

I'd recover the R134a and then add 25 to 28 oz. R134a. Remember: nothing with any sealers, and do NOT add any more refrigeration oil. You won't get a full 12 oz. from each can either, as you'd be bleeding the lines and not all will exit the cans. So figure about 2.5 cans.
 

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^ Agreed, Don't Add Any More Oil. Maybe 2 ounces at most on a complete refill from empty but 1 Ounce is more like it. From what i understand, excess oil wont trash your system or anything but it just wont cool as well as it should. Could be a gimmick, but i think that PAG Oil with ICE 32 in it really works. Could just be all in my head tho
 

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Discussion Starter #20
I am going to have to start over. I cannot get the blue below zero on the 134 line. That is putting 55 at the vent.

I also found the low side valve is leaking. When I started unscrewing the cap, you heard the pressure release
 
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