I had "help" from the manager at the auto parts store who added a full R134a can upside down "cause it's quicker" (and poured liquid into the system instead of allowing the gas to be drawn into the system). I filled it 3 years ago and it has been running OK for the last 3 years, but not as cold as new. When I added the stop leak 3 years ago, there was not enough pressure in the can to fill it, but it was at a steady 40 PSI for the last 3 years so there are no leaks.

What do I do now?

I cannot get the pressure to come up beyond 32 PSI and the compressor feels slugged and rattles a bit when it turns on. I am afraid to use the AC until I get it fixed and it's hot out there! It was added on the low-pressure side, so he got that right, but clear as day it says on the bottle "to not turn the can upside down"... It's a 2013 Honda CR-V.

  • liquid or gas going in will always reach equilibrium.
    – Solar Mike
    Jul 5, 2020 at 17:09
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    It doesn't matter, in fact most refrigerant is added "upside down" since it is faster and it doesn't harm the system in any way. I think what's missing here is knowledge and experience on your part. Take the car to a licensed mechanic and get a proper diagnosis. My guess, however, is that you have a leak plus a bad compressor.
    – jwh20
    Jul 5, 2020 at 17:26
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    Adding liquid into the system can damage the reed valves in the compressor. Stop leak is a bad idea, no such thing as a mechanic in a can.
    – Moab
    Jul 5, 2020 at 17:38
  • @Moab While I appreciate the sentiment, 3 Years ago I filled it with a can and have had it working great ever since. It was still working great before the auto guy "helped" me (who was also a mechanic at a dealership - I'd like to put him in a can). So I would have to disagree as my AC was not working and I used a "mechanic in a can" that got me 3 more beautfiul chilly years during 3 brutally hot summers.
    – Dan B
    Jul 6, 2020 at 12:49
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    When you use a can of deodorant it lets a high pressure liquid expand into a gas through an orifice, to get to equilibrium that liquid needs to absorb heat which is fine. If you spray that can from full to empty you will find it gets cold and can block itself due to freezing as it cannot absorb enough heat. You letting liquid or gas into the system will find that the liquid will expand and change state to a gas according to the ambient temperatures and the heat available at the time. As long as it was not running then it should be fine, unless you added too much - which you cannot be sure of.
    – Solar Mike
    Jul 6, 2020 at 13:11

1 Answer 1


It doesn't sound like you are using AC Gauges; they're essential for anything more than a quick top-up (but can be expensive).

My recommendation is to take it to a garage for a full evaluation and refill. They'll tell you what's wrong (if anything) and refill to factory specs (which is hard to do with a can of air from the car spares place)

  • For the record, the "manager" was a mechanic at a dealership, so taking it a mechanic is not always the perfect solution as it was a "mechanic" that did me in...
    – Dan B
    Jul 6, 2020 at 12:46

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