# Is 7% refrigerant loss per year worrying?

I some time ago had my car's air conditioning system serviced, when the car was 2.5 years old. It was functioning okay, but I opted for the service because I wanted to have a measurement of the refrigerant loss. The receipt I have says:

• Recovered refrigerant 437 g
• Removed oil 3 g
• Added refrigerant 530 g
• Added oil 3 g

So, 93 g of refrigerant was lost. In other words: in 2.5 years, 17.5% of refrigerant was lost. This gives a refrigerant loss rate of 7% per year.

My questions are:

• Should I be worried about 7% refrigerant loss per year?
• How often based on this refrigerant loss rate, should I have my AC system serviced?

The car is a 2016 Toyota RAV4 hybrid.

• My "thought" on this is "YES". I'm no expert, but 7% loss equates to quite a lot in just few years. New cars should be good for 10-12 years under normal conditions ... but that's just my thinking ... I could be way off base. – Pᴀᴜʟsᴛᴇʀ2 Jul 21 '19 at 14:42
• Yes, indeed, 0.93^10 = 0.48 and 0.93^12 = 0.42. So, most of the refrigerant will be gone in 10-12 years. – juhist Jul 21 '19 at 16:09
• I could understand 1% (or less) loss per year, mainly because no seal is perfect. Given most of the o-rings/seals will start to deteriorate over time, they'll start to lose more the older they get ... but what you're talking is quite a bit. – Pᴀᴜʟsᴛᴇʀ2 Jul 21 '19 at 16:56

## 2 Answers

Yes , a leak is a leak . If the service information is correct. Efficiency falls as soon as you lose any refrigerant. And you certainly do not to need to lose all before the AC no longer works. My guess is a loss of half would shut it down; An AC tech could answer. My last several cars leaked none ; at least after 6 to 8 years the AC worked as well as when new.

In short, no. How do you know the car was at the correct fill to begin with? What is the capacity on the AC system? Maybe the tech overfilled the system. There should be a sticker in the engine bay with Toyota’s capacity spec. If the car was low on Freon then test it again in the fall after AC season is over and see if you’d had consistent loss and at that time have the shop sniffer test for leaks.

• Well, I don't know either to be honest. I'll think I wait 2 years for the next service, so that I get a more accurate per-year reading. I mean, if the figure is +- 5% accurate, after a year we're talking about 2..12% and after two years we're talking about 9..19% reading. Edit: they indeed overfill the oil (mechanics.stackexchange.com/questions/68721/…) so they could overfill the refrigerant too. – juhist Jul 22 '19 at 7:26