Adding aircon oil after component replacement

[Ian_99]

Hi all!
I have a quick question that I haven't found an answer to right away (google and the workshop manual)... I'm fairly sure the condenser of my AC system is leaking and I'll have to replace it. The AC gas has already completely leaked away so I don't have to worry about that anymore and can freely add some high pressure nitrogen for proper leak testing.

On many forums they recommend to add some PAG46 (or whatever oil it uses) to the system when you replace a component, how much should I add if I were to replace the condenser? I only found a single chart that says 135ml PAG46 is the recommended amount for the whole system, but I don't feel like flushing the whole system as it should be alright, I hope.

I'm by far not experienced with this so apologies if this is a very basic question. I learned how AC systems work, working on them in practice is something else...

[brodfather11]

As I understand when you get your A/C system pressurised the machine adds oil at the same time as it adds the gas.

Are you intending to regas your A/C at home ? I've tried those bottles of refill gas at home and it didn't work out and had to take it to a garage with the proper equipment.

If its for checking leaks with nitrogen then I don't think it would need oil added unless the system is going to be run.

  Someone else may know better

[shtu]

As I understand when you get your A/C system pressurised the machine adds oil at the same time as it adds the gas.

Exactly that. The person regassing the system will vacuum, extracting all oil and gas, test it, then add the correct amounts of gas and oil.

You can get this done for £40-60, even by tyre and exhaust places. I'm all for DIY, but rhis is a job where at least some of it needs to be done by someone with the right equipment.

[Ian_99]

As I understand when you get your A/C system pressurised the machine adds oil at the same time as it adds the gas.

Exactly that. The person regassing the system will vacuum, extracting all oil and gas, test it, then add the correct amounts of gas and oil.

You can get this done for £40-60, even by tyre and exhaust places. I'm all for DIY, but rhis is a job where at least some of it needs to be done by someone with the right equipment.

Thanks for the feedback, I am trying to do this myself, I got the tools I need except for the refrigerant, as I legally cannot get that (I learned HVAC systems in university but getting the needed certification takes too much time and money). What I am planning to do is get the system ready after a leak check and replacing what's leaking, then ask someone with the required certification to put some clean refrigerant in.
The compressor oil is the only thing I need to figure out, or should I just flush/replace the entire system? There's not exactly a guage to check the oil level. As the previous coolant has evaporated by itself I don't know how much oil got out with it.

[shtu]

Exactly. The only way to know what's what is to put the system under vacuum, and the oil is extracted as part of that process, then the correct amount added along with the gas.

Flushing? Can't advise on that, if you suspect there's debris in there it's maybe an idea.

I'd still recommend getting it done for you - iirc Kwikfit won't even charge if the system won't hold vacuum.

[Ian_99]

Exactly. The only way to know what's what is to put the system under vacuum, and the oil is extracted as part of that process, then the correct amount added along with the gas.

Flushing? Can't advise on that, if you suspect there's debris in there it's maybe an idea.

I'd still recommend getting it done for you  - iirc Kwikfit won't even charge if the system won't hold vacuum.

I'm very sure pulling a vacuum does not remove the oil, that'd be very easy in my case. There's definitely some left in the compressor itself.
Flushing the system is the last thing I'd want to do, it's a hassle to take the compressor off and messing with the timing belt, something I haven't done yet.

And the system holds a vacuum just fine. That's why I'm using nitrogen to pressure test to find the leak. Still waiting for a fitting for that.

[smutts]

Does Citroen use R134a refrigerant?
From my VW days, the oil it used for it was hygroscopic, & gets "wet" in a system that hasn't been pressurized for a while.
I don't know how well your vacuum pump would be able to dry it.

[Ian_99]

Does Citroen use R134a refrigerant?
From my VW days, the oil it used for it was hygroscopic, & gets "wet" in a system that hasn't been pressurized for a while.
I don't know how well your vacuum pump would be able to dry it.

There is no label (or at least none that's still readable) that specifies what refrigerant it uses exactly. All online sources I found say it's using r134a, which makes sense for it being a 2008 car. Maybe the compressor label is still readable.

I think at this point it's just best to take the compressor out as the belt needs replacing anyway (it's starting to show cracks) and dump all the old oil. My bets are on the condenser needing replacement so after that I think I can refill it with fresh oil close to it's rated capacity?
If the condenser is still good I have no clue how much oil I should add, besides the amount drained from the compressor, which is my main issue.

[Ian_99]

So I just did a pressure test, and as I expected there were bubbles instantly appearing on the condenser, right behind the fan. Next step is getting a replacement condenser!

[Ian_99]

And now I took out the broken condenser, but ripped one of the connections, nothing I tried managed to get it loose until the connection tore apart. So now I'll be replacing the AC hoses as well... At this point I can just put close to the rated amount of compressor oil? I emptied the compressor and barely any came out.