R134a Capacity

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m240b
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R134a Capacity

Post by m240b »

Greetings once again,

My dads 2003 Toyota Tacoma PreRunner 2.7L is missing the refrigerant capacity sticker that is found under the hood of most vehicles. I also have not been able to find it online by searching forums. Do you guys have this information? His AC is not working, so I checked to make sure the compressor clutch was spinning when the AC was on. No spin, checked pressures with gauges, completely empty. I was hoping to charge the system with 134a and UV dye so that I can find the leak. This is why I was searching for the refrigerant capacity. Yall have helped me fix the ac system on two different vehicles, so thanks again.
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Re: R134a Capacity

Post by Tim »

23oz R134a.
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m240b
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Re: R134a Capacity

Post by m240b »

Well my lazy self finally got around to finding this leak. Plan on replacing condenser and receiver/dryer. Since I am doing this myself, does anyone know the rough estimate of how much PAG oil I should add to the new components? Any help would be greatly appreciated.
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Re: R134a Capacity

Post by JohnHere »

The oil specification for your PreRunner is 7.75 fluid ounces of PAG-46. I would add 1-1/2 ounces to the new condenser and 1 ounce to the new R/D.
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m240b
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Re: R134a Capacity

Post by m240b »

Thank you. Ill post update of my success or failure.
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Re: R134a Capacity

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m240b wrote: Wed Jul 13, 2022 3:50 pm Plan on replacing condenser and receiver/dryer.
I presume you found the leak in the condenser. Nice work.

It's always a good idea to replace the R/D as you're doing whenever the system is opened—especially in this instance in which all the refrigerant leaked out. Be sure to change the o-rings in any joints you have to disturb, and give each new o-ring a light coating of Nylog Blue to help prevent leaks.

To be on the safe side, I would evacuate this system for at least a couple of hours and preferably longer to ensure that you remove all the air and moisture that might have entered. Then let it set for a while and observe whether the vacuum decreases on the low-side gauge. If it doesn't, that's surely a good sign but still no guarantee that the system won't leak under positive pressure. At least you'll be able to verify that the vacuum holds, though.

If you plan to re-charge it using the small cans, be aware that they often contain somewhat less than the amount printed on the label. It's always best to weigh-in the exact charge using an accurate refrigerant scale. Your truck holds just 23 ounces (1.4 pounds) of refrigerant, which isn't much. So cooling might be compromised if a "guesstimated" charge amount is off by only a few ounces.
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m240b
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Re: R134a Capacity

Post by m240b »

The leak was coming from one of the lines that connects the condenser to the receiver dryer. Since I was already going to have access, I decided to replace the condenser because it looked pretty rough. Same for the receiver dryer. I know it's not the best way to do it but I will be using the small r134a cans to charge the system. Ill do my best to be as accurate as possible. New o-rings were installed the joints but I did not use Nylog Blue, fingers crossed. Currently pulling the vacuum as I type this, fresh vacuum pump oil being used with the pump, I was planning on pulling for just one hour, but I will add more hours as you suggested. Will update when complete. Thanks again.
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Re: R134a Capacity

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m240b wrote: Sun Jul 17, 2022 12:03 pm The leak was coming from one of the lines that connects the condenser to the receiver dryer. Since I was already going to have access, I decided to replace the condenser because it looked pretty rough. Same for the receiver dryer.
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m240b wrote: Sun Jul 17, 2022 12:03 pm I know it's not the best way to do it but I will be using the small r134a cans to charge the system. Ill do my best to be as accurate as possible.
Do you have access to an accurate scale? A postal scale will do in a pinch.

Be sure to purge the yellow hose with refrigerant by loosening the knurled fitting at the Manifold Gauge Set for a few seconds. Otherwise, you'll pump in the air and moisture contained within the hose, and you don't want that.
m240b wrote: Sun Jul 17, 2022 12:03 pm New o-rings were installed the joints but I did not use Nylog Blue, fingers crossed.
PAG oil applied to the o-rings before installation also helps seal them.
m240b wrote: Sun Jul 17, 2022 12:03 pm Currently pulling the vacuum as I type this, fresh vacuum pump oil being used with the pump, I was planning on pulling for just one hour, but I will add more hours as you suggested.
Fresh oil in the vacuum pump, especially if it's a loaner unit, is always a good idea, as is a thorough evacuation—a few hours if you have the time.
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Re: R134a Capacity

Post by m240b »

I was able to find the parts that I needed. So, pulled for two hours, closed gauges and held vacuum for one hour and the needle did not move. Charged with r134a small cans and food scale to the best of my ability. Purge yellow hose before opening low side valve. Went from no A/C to 53 degree air coming out the vents so I would call this a success. I do wonder how much colder it would get with a fully accurate charge as opposed to my food scale charge? 3rd vehicle you guys have helped me fix. Thank you once again.
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Re: R134a Capacity

Post by JohnHere »

m240b wrote: Tue Jul 19, 2022 8:43 am So, pulled for two hours, closed gauges and held vacuum for one hour and the needle did not move.
Good.
m240b wrote: Tue Jul 19, 2022 8:43 am Purge yellow hose before opening low side valve. Went from no A/C to 53 degree air coming out the vents so I would call this a success.
I would like to have seen lower vent temperatures than 53°F. What were the pressures and the ambient temperature? It sounds like the low-pressure side might be elevated, resulting in a rather warm-ish evaporator. Did you record that vent temp at idle or at 1,500-1,800 RPM, A/C on "recirc," blower on medium, condenser/radiator fan(s) roaring, and let the system stabilize for a couple of minutes? If not, take it for a test drive with the thermometer in the center vent and see how it does at a good speed when plenty of air is flowing through the condenser.
m240b wrote: Tue Jul 19, 2022 8:43 am I do wonder how much colder it would get with a fully accurate charge as opposed to my food scale charge?
With your set-up and acute awareness of what had to be done, I'm sure that you got the charge close. But if the vent temps don't drop while driving it and you have any lingering doubts, you can always take it to an A/C professional in your locale to have it recovered, evacuated, and re-charged by means of their RRR machine, which will charge it to the precise amount.
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