Issues getting refrigerant to charge

[evan1234321]

Hello,

for the life of me I cannot figure this out. Acquired a new truck, ac blows hot. Manifold gauges I rented at parts store show low and high side are both at zero psi. I ran a vacuum pump for about a half hour or so, then went to add r134a. The truck wont accept the charge. The point of this was to add a charge with some dye, maybe enjoy ac for a little while before it all leaked out, find the leak and fix it. However The Freon makes it into the gauge but sits there. I noticed the compressor isn't spinning, which I assume is from lack of refrigerant. Okay, cool I'll just jump the low pressure switch. So the compressor is now spinning, but Freon will not make its way into the system. low side reads 90psi when I release the valve for the can. Low side is open at the gauge. I dispel air at the gauge and it falls back to zero, and then that's it. High side is closed at the gauge. Car is running with AC on. Any ideas are much appreciated. I would also add that this truck previously had ac and was working.

Respectfully, please fight the urge to tell me I'm in over my head and to take it to a professional. I'm using this as a learning experience, thank you.

 

[Motorcity muscle]

With gauges attached did it show a vacuum with pump on? Have done this before?

 

[07navi]

Don't give up yet there are some ac semi pros in here. Is the compressor spinning now? Is the ac turned on high inside? Do you have the round gauges with the hoses (sold online cheap), are you using the ac cans and how many? Are your Schrader valves(s) free?.

 

[evan1234321]

With gauges attached did it show a vacuum with pump on? Have done this before?

Thanks for the reply. Yes the gauges displayed 30hg on with vacuum pump running. When turned off vacuum drops back to zero. And yes, I'm by no means a pro but I've done a few projects before back in tech school.

 

[evan1234321]

Don't give up yet there are some ac semi pros in here. Is the compressor spinning now? Is the ac turned on high inside? Do you have the round gauges with the hoses (sold online cheap), are you using the ac cans and how many? Are your Schrader valves(s) free?.

Thank you I appreciate it. Yes, the compressor spins when I jump the low pressure switch. Ac is turned on High with fans on max (not recirculating). I have the standard manifold gauges you can rent at AutoZone. The ones with the three lines and red and blue round gauges. I'm using three 12oz r134a cans as the manual stated it required 33oz. By "Schrader valves(s) free," do you mean is there blockage? If so, no. I depressed both high and low side schrader valves just to see if there was indeed zero pressure and I got a little bit to come out, then nothing. I believe the system is completely empty on both sides.

again, I really appreciate any insight. I'm going mad, lol.

 

[Motorcity muscle]

System should hold a vacuum, when you close gauge port on gauges and turn off pump. Need to pressurize system and locate leak. Can use air pressure to check for leak but dry air or nitrogen.

 

[07navi]

It sounds like it is leaking so fast that it wont take any charge, do like Chris said.

 

[evan1234321]

System should hold a vacuum, when you close gauge port on gauges and turn off pump. Need to pressurize system and locate leak. Can use air pressure to check for leak but dry air or nitrogen.

Vacuum holds with pump off and gauges open for about 2 min or so. Is the method of charging via r134a cans unusable at this stage? I was under the impression that the can was enough to pressurize the system on its own. I'm confused as to how an ac shop machine would do any different. Evacuate, vacuum, then charge.. correct? Does the system need initial vacuum to draw in the refrigerant? I will look into pressurizing with air next as you recommended.

 

[07navi]

It sounds like you have a big leak that needs to be fixed first. Use air pressure and soapy water to find it.

 

[fuzzmanmatt]

Are you using the new self-sealing cans? Those suck, sometimes you have to back off the valve on them a bit to get them to work. See if you can find a buddy with a keg, those tend to work better with most gauge sets.
Your system should hold vacuum for hours. Come back and check it now that it's sat, if it's still got vacuum you're good to go.
If that's the case, fiddle with the knobs, jiggle the cans, sometimes you can get those seals on the small cans to release and do what you need. Good luck!

 

[nando556]

Following this.. I have a 2009 and have the same issue with AC blowing hot but it worked well just a couple weeks ago. I bought one of the cans with gauges from autozone but it just shows that it was way over-pressured. Maybe leak on the intake side so over-pressured with air?

 

[07navi]

Self sealing cans have a valve inside so they don't let refrigerant into the air. You can get an adapter for those if you only have the pin type hose fitting or you can use the hose for the self sealing one type. They are moving towards the self sealing ones especially in California. You can save half a can until next year but now they are wanting a deposit on the cans of $10.

 

[Motorcity muscle]

Your system should hold vacuum for hours. Come back and check it now that it's sat, if it's still got vacuum you're good to go.

System has to hold a vacuum. As Fuzz said for hours, if not, fix the leak and then re-ck.

 

[Goofy173]

Thanks for the reply. Yes the gauges displayed 30hg on with vacuum pump running. When turned off vacuum drops back to zero. And yes, I'm by no means a pro but I've done a few projects before back in tech school.

Bad, bad leak. Obvious but may be hard to find.

 

[tommyddsr]

So, common leak area is the block at the back of the compressor. Also since you tried to put refrigerant in it and had gauges on it, a stuck Schrader valve is also a possibility. Other than that chasing leaks is probably best left to the A/C guys.

 

[SEPTIC PROFESSOR]

Dude, they all fail pretty much at about this age, common known issue for guys on the forum who do their own work.

 

[07navi]

Chasing leaks is not hard, just put the dye in and get the yellow light.

 

[Utah Driver]

How about some pictures of your setup? Sounds like your hose coupler is not correct.

 

[max78]

If it holds vacuum for 2 minutes then it should hold refrigerant for a few minutes as well. Lets make sure your equipment is even good first.

Check the rented gauges are in good working order. I have seen them with bent pins and screwed seals. Check the pins for obvious damage and proper range of motion. Check the seals are even there, and they are not torn or worn, do NOT over tighten the hoses to the gauge, finger tight only and not even that tight really. I have seen rented sets missing seals, or damaged. I over tightened a set and that pushed a seal into the gauge causing a restriction into the system, and a leak out of the hose. I did not tighten it that much at all, it was really easy to do.

Out of the 20 or so times I rented gauges, 2 of them were damaged and did not work. I had a few more with bad seals that gave me issues. people around here must be really hard on stuff.

Connect high and low side hoses.
Screw the knobs down to open both high and low valves (blue and red). Sometimes screwing them down too much causes issues, be careful and back off a turn maybe?
Open the blue and red knobs on the valve manifold
(If applicable) open the center valve that is connected to the vacuum (usually Yellow).
pull a vacuum for around 15 minutes.
With vacuum pump running close the center valve (usually yellow) then turn off pump.
note vacuum level on paper or take a pic of the gauge.
Let sit for 15 minutes and look at vacuum level.


If the gauge visibly moves right after shut off then you have a major leak. trying to fill with dye refrigerant should still be tracible because its still coming out. The Schrader valves are a super common leak point if there is no leak detected at any other component.