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Hole in my condenser - plan to replace myself - question with reinstall order/procedure

treminga on Tue September 17, 2013 4:13 PM User is offline

Year: 2003
Make: Audi
Model: A8L
Engine Size: 4.2 V8
Refrigerant Type: R134
Ambient Temp: 70
Country of Origin: United States

This is my first time posting and have read though a lot on this forum. Been very helpful, but though I would ask to just be 100% clear.

I found a small crack in my condenser about a week ago. Looks to have taken a rock chip along the horizontal fins (very small crack). Car started to smoke a bit from that location and upon returning home found the area to be a bit oily and the AC was not cold. Found the small crack and moved forward with procuring parts.

Purchased a used condenser from a trusted person that had to replace their compressor and decided to replace the whole system while they were in there. He also recommended purchasing a new dryer/accumulator since mine has now been exposed to the elements for about a week.

I don't plan to refill the system myself. Plan to take it to a trusted mechanic.
It was suggested (and I think completely valid) to manually flush the condenser off of the car since it was used. Assuming NAPA or similar store will have flushing fluid for this. Was told to push compressed air through both sides for a while to make sure all fluid eventually came out clear (or same color).

My question is can I then go ahead and install the condenser and dryer, close up the system and take it to a mechanic? I can then have him preform a full system flush and refill of the refrigerant. I just wanted to make sure I could assemble the car with the new parts and then drive it to him? I plan to drive with the AC system completely off on the way to the mechanic just to be safe. The parts replacement seems simple enough and I'd like to save as much labor as possible.

My last question, what would the estimated charge be to flush and fill the system again?

Thanks so much!

Leggie on Tue September 17, 2013 6:04 PM User is offline

If your A/C isn't completely discharged yet, add a can of refrigerant ASAP. The purpose is to keep the system under positive pressure so that it is leaking out slowly to prevent ingestion of contaminants. This would alleviate the need to flush.

Before you disconnect the condenser, clean the mating area with paint thinner(preferably deodorized type) and rags. Paint thinner is much less damaging to plastic parts. The reason you do this is to minimize the chance of introducing junk into the system.

Blow out your old condenser with air into a clean, preferably white or clear container. If you don't see debris, then you don't need to flush. Flushing is more likely to cause problems than prevent it.

It was a mistake buying a used condenser from someone who had a blown compressor. It will very likely have shrapnel from compressor disintegration. This piece should be flushed. If you see metallic fragments in the drained solvent, I would go buy a NEW condenser. If you put this in your car, you risk damaging your compressor unless you can get it completely free of debris (unlikely and very time consuming)

Edited: Tue September 17, 2013 at 6:19 PM by Leggie

HECAT on Tue September 17, 2013 9:51 PM User is offline

Your technician will need the system open to flush the individual components; if he will flush, or has the appropriate tooling to do so. You cannot flush an assembled system.

You should ask your technician if you can work together to reduce your costs, and what his fees will be for his services. Some technicians will see this as risky, and others will see this as taking the margins they could have gained form the parts and labor install, so I would make this relationship and arrangement first.

I would not be surprised if the technician tells you to install a NEW condenser and dryer and bring it to him so he can add oil, vacuum, and recharge.

Your trusted friends condenser was junked from his car, and he charged you for it???? I would give it back (you do not need that headache).

Hope this helps. You can read the PDF file below to understand more about flushing.


HECAT: You support the Forum when you consider for your a/c parts.


webbch on Tue September 17, 2013 10:56 PM User is offlineView users profile

If ever there was a time to NOT install a used condenser, this is it. It's already been through a bad compressor and is no longer a condenser - it is now a giant heat-conducting filter, and a poor one at that.

If you're bent on using it anyway, make sure it's flushed VERY well with PROPER flushing equipment - not that flush-in-a-can stuff.

Edited: Tue September 17, 2013 at 10:57 PM by webbch

mk378 on Wed September 18, 2013 1:12 PM User is offline

Yes the reason it's recommended to replace the condenser after the compressor fails is because you get bits of metal from the old compressor in the condenser. The one your friend had really isn't good for anything except to get a few bucks when you recycle it. Buy a new condenser or at least a used one from a parts car that still had a good compressor.

Edited: Wed September 18, 2013 at 1:13 PM by mk378

treminga on Wed September 18, 2013 4:55 PM User is offline

This was all very helpful!

Here is my next question... if I toss the used condenser before installing, and purchase a new one will I still need to do a system flush, or can my mechanic just refill the system?

Again I plan to replace the condenser and dryer.

I would really like to put this together and hand it over to the mechanic for filling only. I believe my system uses R-134 w/PAG oil if that helps.

mk378 on Wed September 18, 2013 5:04 PM User is offline

For a simple hole in the condenser, you don't need to flush(*). Add a small amount of oil to compensate for the new condenser and drier being dry.

(*) Unless, like Leggie said, the car has had zero pressure and a hole in the condenser for a while. Then you have to be concerned about water contamination. PAG oil is a "polar" substance, it is more like brake fluid than oil in that water will mix with it, and it is impossible to separate the water out later. The contaminated oil would need to be flushed out and replaced with new oil.

Edited: Wed September 18, 2013 at 5:10 PM by mk378

treminga on Wed September 18, 2013 5:16 PM User is offline

Gotcha, its been about a week with the car off, nothing has been pulled off and replaced yet, that is this Sunday. Then looking to take the vehicle in to a shop to have it evacuated and filled.

Most of the shops I have called don't do a "flush" basically both said they evacuate and fill the system.

Leggie on Wed September 18, 2013 7:39 PM User is offline

Oh, replace every o-ring in the connection you break. When assembling, wipe the area well, then lubricate the o-ring area with compressor oil. This helps them seat correctly instead of getting snagged and pinched. If you pinch or snag an o-ring replace again, don't try to save them. It will come back to you later as a small leak.

You don't need to flush the new condenser, but you should still blow it out with air to let out possible junk. Airsept makes little push-in filters for compressor. It is like a faucet strainer filter. If its easy to get to, this is worth installing. If not, no sweats.

Don't over torque. If in doubt, stay on the side of too loose. You can always retighten. Aside from the compressor, OEM AC fittings are among the most expensive parts to have to replace.

Edited: Wed September 18, 2013 at 7:41 PM by Leggie

treminga on Wed September 18, 2013 9:55 PM User is offline

Thanks for the input, I did prepurachase all new O-rings that would be exposed. Are there different types of PAG oil. I know my car takes R-134 PAG. If I only lost the condenser and dryer in the mix, do I need to add much new oil to the system? I thought it was mostly for a compressor failure that would cause a drop in oil that would need any real replacement?

webbch on Wed September 18, 2013 10:31 PM User is offlineView users profile

Yes there are different types of PAG oil. Not sure about the 03 - capacity listings on this site only go up to about 2000.

All the oil doesn't stay in the compressor - it circulates as the refrigerant flows, which is why you have to add a little bit when you replace the different components. Generally you want to try and measure how much oil you remove in such cases, and add back that amount, and an additional approximate amount to cover any other expected losses. It's simply an educated (or uneducated as the case may be) guess. It's common to add about an ounce (total) of oil when replacing the condenser, unless you drain substantially more out of the old condenser - then add back that amount.

Edited: Wed September 18, 2013 at 10:31 PM by webbch

treminga on Thu September 19, 2013 9:08 AM User is offline

Sounds good, so I will make sure to pick up some PAG oil (will look into the correct type) and add that into the new compressor before install. Also looks like I should be lubricating any O-ring with the same fluid so I should get some anyways.

mk378 on Thu September 19, 2013 11:35 AM User is offline

Use mineral oil or the Nylog compound on o-rings. PAG oil should not be used there because of the water issue (half of the connection is "outside") which can lead to corrosion.

Chick on Fri September 20, 2013 2:26 PM User is offlineView users profile

Your Audi uses a Denso compressor.. Pag 46 oil is recommended.. I agree, use Nylog on all O rings
hope this helps...

Nylog Assembly lube

Email: Chick


Freedoms just another word for nothing left to lose

Edited: Fri September 20, 2013 at 2:27 PM by Chick

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