Automotive Air Conditioning Information Forum

Hello I am new to the board, I was directed here from the TahoeYukon forum.

Here is my issue, I replaced the condenser in my 2017 Tahoe due to leaking which is a major problem with 2015-2017 units. As an FYI - the system is 1234YF.

After replacement, I vacuumed the system for one hour down to -28, shut all the valves and let it sit for 2 hours and vacuum maintained.

Upon trying to recharge, I noticed there was no high pressure being reflected and the induction of the freon was very slow probably 5-10 minutes. BTW - I did bleed the air from the input line before trying to feed the freon on can #1. After can #1 emptied I shut the low side valve and connected can #2, the uptake on it was almost zero. At that point the low side pressure was up to 70-80 psi and no high side pressure. The compressor was running.

I shut the low side down closed the can and shut the vehicle off. at shutdown, the air coming out of the vent in the vehicle was 100 degrees the ambient temp was 81. So here I am stumped as to what the issue(s) are.

Any feedback would much appreciated.
Tim

Make sure your high side coupler is seating correctly. With low side pressure, you should have some static readings. Even if the compressor is not turning.

Would the high side coupler being messed up cause the system to not ingest Freon after taking in one 8oz can and reflect higher than normal low side psi?

Thanks,
Tim

Tim wrote:Make sure your high side coupler is seating correctly. With low side pressure, you should have some static readings. Even if the compressor is not turning.

Would the high side coupler being messed up cause the system to not ingest Freon after taking in one 8oz can and reflect higher than normal low side psi?
The static low side readings with the car shut off are currently 70 psi

Thanks,
Tim

Would the high side coupler being messed up cause the system to not ingest Freon after taking in one 8oz can and reflect higher than normal low side psi?

To answer your question, No , you don't even have to have the high side connected to the gauges when charging (although it is advised). Those couplers can be tricky to fully seat correctly. Also, its not unusual for R134 to flow slowly from the can. Sometimes I will place the can in some WARM - NOT HOT water to get it to flow quicker - charging does require patience.

The cheaper gauge sets seem to have coupler issues all the time.

Thanks Guys for your feedback.

I finally figured things out, the gauges are a cheap set because I had to buy ones which had 1234yf couplers,etc. As it turned out the couplers were not quite connected properly so I had to fiddle with them to get correct readings and flow. The other thing I found out was to not tighten the can too tight on the piercer and feed tool. I tighten it down pretty tight as not to leak, as it turned out it was restricting the flow from the can.

I was finally able to get things going however I still seem to have lower than manufacture recommended pressure. The outside temp was 85 and the chart states 40-50 PSI, I am currently at 30PSI. The high side pressure is at 175 psi which is also low compared to spec, it should be around 200 psi. I think I put in the recommended amount based on the tag under the hood (29 oz). The reason I say I think, due to the coupler issues I am not absolutely convinced all 29 oz went in?

I am reading 58 degrees at the vent so I know its operating at some level. I am tempted to try to introduce additional FREON until its at the recommended PSI. However a can of the 1234YF is like liquid gold at $44 per 8 oz can and I don't want to over charge it either.

Thanks again for your help!
Tim

I went and bought a cheap $20 digital scale from Harbor Freight a few days ago because I was always guessing/hoping that I had got the right amount in. The pros charge by weight scales to be 100% accurate on the charge.
What happened when you tried to add more refridgerant? Did the pressures go up? 58 degrees can feel ok but its capable of 50 or less.

I decided to add another can to try and bring the pressure up to what the specs state which at 80 degrees is low side 40-50 PSI and high side 175-200 PSI.

I ran the can in and the vent output temp dropped to 49 degrees, LS was at 35 psi and HS at 180 psi. I decided to button it up and drive it and monitor.

This vehicle uses 1234yf and based on what i have read has a little different pressure than R134a but close.

I drove it yesterday around and the outside temp was 91 and it seemed to keep up OK.

Thanks a bunch for your feedback, I am in no way knowledgeable about auto AC systems. I know more now however.

Have a good rest of your weekend.
Tim