Automotive Air Conditioning Information Forum

I have a 2015 Hyundai Santa Fe with about 160k miles. The A/C system has had a very slow leak for several years. If charged in the spring, I could get well into summer and fall without recharging. Recharge was just attempted. Attaching the meter/r134 to the low pressure side and shaking the can back and forth, I thought I was making headway but then the needle suddenly popped into the red area of the gauge. As I had previously bled the system (only warm air cam out) I was surprised because the r134 wouldn't go in, almost as though the path through the tubing was blocked. Any chance I can fix this without going to a garage? Many thanks for help.

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I see several red flags.
It sounds like you are using a charging kit from the local auto parts store since you mentioned the needle was in "the red zone"
A pro gauge set does not read this way. Also, the little gauges attached to the charging hose of such a kit are notoriously inaccurate.
Then, many if not most of these kits contain sealer, which will really gum up the system badly, and can actually destroy the system.

"As I had previously bled the system (only warm air cam out)". How do you know it was only warm air, and not refrigerant or a mix?

"As though the path through the tubing was blocked". It could be blocked by an ill-fitting connector, by sealant, by a blockage within the internal system of the car, or other problem.

If you can address these questions we can offer continued help. First and foremost plz look carefully at the can of refrigerant you just used and note the contents to see if there is sealer or other additives in it. You only ever want pure refrigerant.

The r134 was pure. A second can I tried did contain sealer but almost none of that ever got into the system. I will toss that. Actually very little of either can was taken in. Also I tried two different charging kit cables and the gauges behaved identically in both- going into "overcharge" in a very short time with little evidence the cans were emptying. As for the "warm air" prior to charging attempts, I detected no r134 odor at all. Thank you for replying! Any other thoughts? Thanks again.

Is it possible that the refrigerant won't come out of the hose because the valve is stuck or hose clogged. How much pressure needs to be put on the valve at the end of the hose to open it? I tried to depress the stem to no avail.
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I would suggest getting an actual gauge set.
https://www.ackits.com/mt1416-santech-r ... oses-24615

Agree.

I wasn't aware that 134 had any odor. What you may be detecting is the slight odor of the oil. Not sure how truly diagnostic of air in the system that is. How could the system fill with air?
Since you have had a leaky system for a while, the amount of oil in the system may be low and thus you may not be smelling it. It could be anything.
In past years, did the refrigerant cans you used have sealer?
Get the proper manifold gauge set and get us some readings before you go any further. Just connect the low and hi sides and give us static readings (with the AC off. Do not try to engage the AC compressor until we get further along)

Hopefully we can get you to the point of finding the leak, fixing it, and vacuuming down and restoring proper oil and refrigerant charge. But we are a long way from that right now. Fixing that leak will be paramount. You are chasing your tail at this point.
Let's see what info you are able to come back with.

Thank you. I hate to say it but I may have to give this to a professional. My time for my own repairs is very limited these days. I do know you guys will guide me along the way. As for the sealant, I do not think I have used much other years. I do know that shelves seem to be loaded with r134 with sealant- almost impossible to find pure r134. I guess that means folks will have lots of problems down the road.
This is a great forum! You guys give very detailed and thoughtful analyses, unlike what you see in other groups. Keep up the good work!

Please provide follow up if you can, it helps everyone who comes to this forum.
Good luck.
And yes, anyone who has used sealer is in big trouble. We call those kits 'death kits'. They should not be sold.

The way to get pure 134 is to get the 12oz cans of pure 134 at Walmart or an autoparts place, and using a pro-type manifold gauge set, and a can tapper, and fill your system that way. No sealant involved.
The other problem with the death kits is that the hose is full of air, which is injected into your system along with the freon and sealer. The LAST thing you want in your system is AIR!

Latest update: The car was taken to a professional. He attempted to charge the system and found same condition as I did: Could only charge the system partially. I had previously found that I could only get about one can in, then back pressure ran the gauge into the red area. Using professional charging equipment he found the same thing. The compressor did not turn on. He will continue from this point tomorrow. In your opinion, what is the next thing he should do? Please eliminate sealer as the cause of this as I have not used any for at least the last two spring chargings. Thank you.

What were his hi and lo side readings.
We need more actual data. Did he test the clutch coil for continuity?
If that was OK, did he test the on-board control circuits. We are just guessing right now.
Are you sure he is a pro?