Rapid automotive A/C decompression - Does oil escape?

[Lakewood Brian]

Well this question got interesting. I found a 2,500+ page service manual online, I think it's from Mitchell1. It looks legit. Buried in this giant PDF is a procedure to do exactly what I'm doing - "Part replacement due to sudden leakage". I copy/paste the procedure below. With my PDF annotations.

As you guys thought, replacing an ounce of PAG oil with the hose would be a good idea. Actually, the manual suggests 35 ml (a bit more than an ounce). But I also need to change the dessicant bag, and the manual suggests another 55 ml (nearly 2 additional ounces) when you replace that. Whoa, that's 3 ounces of oil! (the missing key step I point out below is failing to verify the system is leak free before refilling).

So now I'm left with the dealer, who didn't expect a need to refill ANY oil. 'Conventional wisdom' of an ounce won't hurt and is probably smart. And this shop manual (Mitchel1?) that says three ounces. Agh.

In case you're curious, I found this procedure in the HVAC part of the manual --> INSTRUCTIONS FOR OPENING AND PART REPLACEMENT IN REFRIGERANT CIRCUIT. There were two subsections, the first to replace parts due to minor leakage, the second to replace parts due to sudden leakage. In the section for minor, gradual leakage, it calls for replacing 20 ml for the desiccant pack and 10 ml for each replaced AC line.

 

[Lakewood Brian]

Thanks again to everyone who helped out on this thread. Here's my hopefully last update. I bought a subscription to Mitchell1 manuals (fan-freaking-tastic, BTW). The manual screenshots I posted are the same as on my Mitchell1 manual subscription.

Total recommended = 35ml for hose replacement + 55 ml for desiccant pack replacement = 90ml. That sounded like a LOT of oil, considering the above conversations and that I found zero oil residue where the hose split. Actual added = 75g (a little less than 3 oz). AC blows 40F with ambient temp 71F. That was the last warm-ish day we had here. I'll test again next summer.

And I found my long-time frustrations w/ AC services is related to my cheap Harbor Freight AC manifold. I borrowed manifolds from O'Reillys and Autozone and compared the three and learned a lot. A good manifold is worth the expense.

I'll update this post if I have problems related to over/under filling.