Hey Scotty, I got a 2009 Honda Civic with an automatic transmission. About a year ago my air conditioning started blowing warm and found it needed a recharge of refrigerant. I used one of those cans you can get from an auto parts store and it worked. Now its blowing warm again but still has plenty of refrigerant. Is it caused by a potential air bubble from the can hose that can be fixed by evacuating the system and recharging or is the compressor starting to go out? The car has about 198000 miles on it and everything else works great.
There's really no way to positively know if you have enough refrigerant or any air in the system.
(short of evacuating the system and weighing the recharge)
But an "air bubble" isn't preventing your A/C from working.
There is a way to know if your compressor and fans should be turning on, or if there a "clog" between the high side and low side. Buy a cheap set of A/C gauges and hook them up after the car has been sitting. (STATIC PRESSURE)
Engine OFF the pressures on both gauges should be equal (means no clog or that impossible "air bubble" you're concerned with).
Also, both gauges should read about the same as the outside air temperature.
So on an 80 degree day, both gauges should read about 80. If that's the case the A/C clutch should engage when you turn on the A/C. (How long it stays engaged depends on other factors like too much pressure or not enough pressure).
If the compressor doesn't engage, I'd start chasing down an electrical issue.
Compressor relay fuse/compressor relay.
If the Condenser Cooling fans don't kick on with the compressor then, Cooling fans burnt out, Cooling fan relay fuse/Cooling fan relays
Understand that you can charge the A/C system with compressed air. (it wouldn't cool) As long as it's within the Low/High psi limits the A/C clutch will engage and the compressor will run.
Of course with the moisture content in the air and the lack of any lubricant, the compressor would quickly implode.
In your case the STATIC PRESSURE will say a lot. If it's 80 degrees outside and both gauges are reading Equally but much lower than 80, AND THEN AFTER seeing if the High and Low pressure on the gauges is low with the A/C running,
AND because you added refrigerant to it a year ago and it started working, I'd make the call that it's low on refrigerant again.
(Refrigerant doesn't "disappear", if it got low it leaked out)
It's summertime and there's a lot of A/C questions on the forum.
I searched out a couple of videos that will help people understand A/C problems and grasp the way the system works.
In the 1st video the guy does a pretty good job of explaining the basics.
In the 2nd video, ScannerDanner uses compressed air On A Completely Empty System to get the compressor clutch to engage for a few seconds and uses soapy water to search for leaks (and explains why his reasoning isn't "completely insane). Not relevant to your issue but I found it interesting and he does dispense some valuable information along the way)
https://www.youtube.com/watch?v=QKmbO3rAd3Q
https://www.youtube.com/watch?v=m5XM5Ak55gU
(neither of these guys have a fraction of Scotty's followers/audience so I hope posting their videos isn't a violation of the forum's Terms of Use. The moderators will correct me if it is)
If the can you used had sealer in it that could have clogged up your expansion valve or other parts of the AC system. On those "recharge" cans frequently there is no way to purge air out of the line if it came with that attached.
Best to have an AC technician look at it, but if that refrigerant can had sealer in it warn the shpp since it can damage expensive equipment which you would be responsible for.
I checked the can and it does. Feeling pretty stupid that I didnt notice it when I bought it. What can this run me for taking it in to get fixed?
Unfortunately that's the case with a lot of those "recharge" cans. Don't know what it's going to cost, really depends on what's wrong and how badly the sealer is going to affect things. Best bet would probably be to take the car to a good local AC shop (NOT a chain like Pep Boys or FIrestone) along with the can so they can see what you put in, and ask.
Unfortunately, no shop I know of will touch a system with stop leak in it. It reacts with moisture and theoretically plugs holes, because moisture gets c in at the leak. Most people don't fully understand how to service the air conditioner, and the sealer clogs parts of the car's A/C system if moisture got in there and wasn't removed. It destroys fancy recovery equipment by clogging it the same way. You'll have to replace everything in the A/C system to be sure you fully get the sealant out.
I'm not surprised, the sealer really is destructive. A friend of mine some years ago used sealer in his AC system and didn't tell me when he asked me to look at it. In my case it "only" ruined a $50 manifold gauge set instead of a $5000 recovery unit at a shop. (He wound up having to replace the entire AC system because the sealer made such a mess of it.)
I've never messed with the stuff but read plenty of horror stories when I was familiarizing myself with the practicality side of A/C work. I had the theoretical stuff down thanks to engineering school, but have no formal HVAC training. I spent a month doing research on stop leak and proper A/C servicing before tearing apart my my old Ranger's 22 year old A/C. I spent $700 on everything and did a proper servicing. It paid off, the air conditioner freezes me out now. Haha. I bought my manifold gauges and vacuum pump if I ever want to repair more of them. Stop leak will be my first concern if I ever do it on the side.
I don't know if shops have some way they can test for the presence of the stuff, they must deal with it all the time. If someone buys a used car they might not even know that sealer is in there.
Maybe the site should have a sticky post about this. A lot of people seem to be ruining their air conditioning with these snake oil recharge cans that promise you can just "fill to the green" and leaks will be magically sealed. Aside from the problem with sealer that just about all those cans contain, on a modern AC system with a variable displacement compressor you can't judge the charge level by system pressure. Those crappy color-coded low side gauges are virtually useless.