Air conditioning and pag oil.

[Adamdavid899]

Howdy, since the weather is getting nice I took the trouble of replacing the entire condenser on my A3 2.0tfsi.

(Entire front end unbolted and folded forward to pull the rad pack out.)

I have an ac evacuation and recharge station at work. With the capability of adding pag oil to the system, does anybody know the capacity of oil required.

I have charged the system and it is working. However I fear that it doesn't have enough oil in and I'd really not want to bother to take the risk of the pump seizing up! Rather than going through the trouble of pumping the pag oil through the AC machine, could I evacuate the pressure first and then take the hoses off the top of the pump and just pour it in? That way I know it's definitely gone in and not left some in the refrigerant machine. Since the hoses are easily accessible from the engine bay.

Anybody know the quantity required, or has done a job like this. Usually I don't care and would just recharge it but I'd like this car to last somewhat and not be replacing everything At any given moment.

Many thanks

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[gary3306]

What year is it? Because it will be somewhere between 8oml to 115ml and either PAG46 or PAG68 dependent on year. It will also depend if you have a Denso or Delphi compressor fitted.

 

[Adamdavid899]

What year is it? Because it will be somewhere between 8oml to 115ml and either PAG46 or PAG68 dependent on year

It's an A3 8p bwa engine 2006.

Thankyou

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[gary3306]

Denso comp 90ml, Delphi comp 110ml of PAG 46 (you'll not do any harm in putting 100ml in whatever comp it is.

EDIT:Actually scrap that, I was looking at the wrong line . If its a Zexel, Valeo or Sanden comp it takes 115ml of PAG46. If its a Denso 7SEU17 comp, it takes 140ml of PAG46.

 

[Adamdavid899]

Denso comp 90ml, Delphi comp 110ml of PAG 46 (you'll not do any harm in putting 100ml in whatever comp it is

Thankyou, the next question would be how do I know how much oil is already in the system ? Since I'm guessing some would reside in the pump after just changing the condenser ?

Really appreciate your help.

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[gary3306]

If you used a recovery machine and vacuumed down the system to boil off moisture (which you should most definitely do when changing components/servicing the aircon), then there won't be any oil left in there. The machine will or should clear the system of refrigerant, oil and dye.

 

[gary3306]

If you want to put oil in yourself, you can get little canisters of PAG oil that go into a similar piece of kit that you put tubes of silicon into to do round your bath etc. These canisters screw directly onto the A/C ports and you just inject the oil. You can do the same with the dye if you need to put some in to find leaks.

 

[Adamdavid899]

If you want to put oil in yourself, you can get little canisters of PAG oil that go into a similar piece of kit that you put tubes of silicon into to do round your bath etc. These canisters screw directly onto the A/C ports and you just inject the oil. You can do the same with the dye if you need to put some in to find leaks.

View attachment 185718

Thankyou, well I was thinking of buying just a can of pag oil and using the machine since its much cheaper.

I've seen a can of liquimoly pag oil for around 15 on the net.

That's if it's the right grade etc I'll check up now I've seen your post!

I work at a breakers yard, so my main job is pulling cars to pieces and not fixing them , although I've worked at garages before so I do have a decent bit of knowledge.

I'm just not well up on AC stuff really, I know it's all specific stuff or the pump will go bang.. when I changed the condenser it was rotten and I first tried to fill it thinking it was just empty and could hear it coming out. So I bought a brand new condenser.

When I pull cars to pieces. If I drain the refrigerant system sometimes after I pull the engine to bits and stand the AC pump up the green oil comes out still. This is why I was thinking some could still reside in the system.

If my car had a leak and all the AC gas came out. I'm not sure how long it's been dry for etc. I just want to be sure to add oil and not too much before I use it!



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[gary3306]

You absolutely need to have it on a machine once you have all the new bits on to boil off all the moisture by letting the machine vacuum it down for at least 30 minutes, then let the machine fill it with refrigerant. If you don't, and there's moisture still in there and I guarantee you there will be, the aircon will cycle warm and cold at best or not work at all. A specialist is the decent way to go. I normally vacuum down for an hour after a break in the system to replace items. The result is icy cold aircon

You didn't mention if you'd replaced the Drier? You should ALWAYS replace the drier when replacing parts on the aircon. Its just good practice. You wouldn't put new brake discs on and refit your half worn pads (ok some would lol)

 

[Adamdavid899]

You absolutely need to have it on a machine once you have all the new bits on to boil off all the moisture by letting the machine vacuum it down for at least 30 minutes, then let the machine fill it with refrigerant. If you don't, and there's moisture still in there and I guarantee you there will be, the aircon will cycle warm and cold at best or not work at all. A specialist is the decent way to go. I normally vacuum down for an hour after a break in the system to replace items. The result is icy cold aircon

You didn't mention if you'd replaced the Drier? You should ALWAYS replace the drier when replacing parts on the aircon. Its just good practice. You wouldn't put new brake discs on and refit your half worn pads (ok some would lol)

The machine I use for work automatically knocks off once the pressure has been relieved.. vice versa once filling..


Also the condenser I purchased has the canister on the side.. is this the dryer? If so then it's new.

Many thanks

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[gary3306]

The machine should have an option to vacuum down. Yes the canister will be the drier

 

[Adamdavid899]

The machine should have an option to vacuum down. Yes the canister will be the drier

Ah good stuff..

So the machine only has three options.

Evacuation

Charging

And another option which releases the pressure stored in the machine to an external bottle. ( This may be called evacuation ) can't remember.. one or the other vents from the vehicle to the machine and one vents from the machine to a bottle.

However it's got no buttons to alter anything.. it's got a turn dial to select evacuation or charging.. or the other option. then a power on/ off switch.. and a bunch of lights to determine status.

It's pretty vintage though. Looks about early 2000's era.

We only really purchased it to clean the cars before we open the ac system as that stuff is some nasty gas. It does that fine. It does charge the system well though. It's got a hose for high and low ports.


I charged it and left it running for half an hour and it doesn't cycle between cold or hot.. it is working fine I'm just paranoid about it having no oil because I didn't put any in and if it's had a leak it probably or definitely will need some!

I really appreciate all the advice by the way.




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[gary3306]

it'll be just a basic recoverycharge unit. A proper service machine would vacuum down. I have a TEXA Konfort machine which is the dogs equipment. If it's cold thats all you need mate, good stuff

 

[Adamdavid899]

it'll be just a basic recoverycharge unit. A proper service machine would vacuum down. I have a TEXA Konfort machine which is the dogs equipment. If it's cold thats all you need mate, good stuff

Yeah thats the one, I'm guessing like you say under a vacuum water will boil causing it to be evacuated too, but how can it get oil from the lowest parts of the system up through the port which is at the top?

Surely there must be some oil left over.. unless there's that little of it once it's cycled through the system evacuating the pressure out takes whatever oil with it in one way.

I know for sure this one doesn't do that because once the pressure gauge for the vehicle hits zero it clicks off on the relay.

I don't think I'm going to beable to do a proper job though with the machine I have then due to the fact I can't vacuum down :/

What are the consequences of adding too much oil? Say if it already had 50 ml and I put another 100 in.

I pretty much know what would happen if I didn't add any



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[gary3306]

If you overfilled it, and it boosted the pressure in the system enough, it would initiate the high pressure switch, would would cut in to protect the system particularly the compressor. This would be evident if you hear the compressor kick in but immediately kick back out again. It would repeatedly cycle like this. Some oil is better than none, so put 75% of what is normally required in. That way, if it is meant to have 100ml in for example but it already has 50 in, you put in 75ml it will then have 125ml in, which isn’t way over the top

 

[Adamdavid899]

If you overfilled it, and it boosted the pressure in the system enough, it would initiate the high pressure switch, would would cut in to protect the system particularly the compressor. This would be evident if you hear the compressor kick in but immediately kick back out again. It would repeatedly cycle like this. Some oil is better than none, so put 75% of what is normally required in. That way, if it is meant to have 100ml in for example but it already has 50 in, you put in 75ml it will then have 125ml in, which isn’t way over the top

Thanks man I really appreciate all this!

I'll get some oil for Monday and see how she goes.

It does get pretty cold now I think I'm just paranoid about it blowing the compressor up. Even though I more than likely have one knocking about knowing Audi's it probably isn't that easy of a job

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