Do ya need a machine to recharge AC system?

[bluegill]

Ok guys, I still don't have AC in my car 2 years after being a dummy and disconnecting the condenser hose to remove the bumper for a timing belt service.

I have tried to recharge it after replacing the receiver drier and pulling a vacuum, but it will not take a full charge from cans. I think the system is so low that the compressor won't kick on to pull more R134a, and the cans don't have enough pressure to fill the system to that level. Is a machine needed to recharge? Will I need to take it into a shop?

Other questions: the replacement drier doesn't fit the OEM bolts and fittings would need to be bore out to accept the right bolt size. Can an AC shop do that or should I just throw it away? What would it cost to replace and full recharge? I figured winter may be a good time for business to get a deal.

[EvolutionArmory]

If you opened the sealed AC system, you have a ton of air in the system. It’s best to get a proper vacuum and refill.

[oVeRdOsE]

well, I did not use a machine on my 96' nissan maxima, and it worked ( purge and fill with the autopart gas cans r22a). It worked for 5 years, then I sold the car in 2015, and still working!.

A4 b7 got a very simple ac system, it could work, but I wouldnt try it. few months ago I went for a refill, and it took about 45minutes- 1h. The machine purge the line, dry the line, and ajust the perfect qty and pressure.

at the end, if your b7 is a beater, try it with the r22a or r134a cans if your state allows it, and report. But my guess will be that youll have trouble with air.

If its not a beater, go to a proper place, and do it right the first time (100-150$ for a purge and refill).


the dryer got a big aluminum part at the top, if you're lucky, you can try to force the screws, but it might result of a leak. dryer are cheap, try to get a new one. also , it's very easy to change.

ac in winter is very useful to defrost and reduce hu% in the car.


Note : if you have a leak, it could be the pressure sensor on the condenser (driver side). The gas can leak through the connection pins. That was my trouble.

[Der Konig]

Just a thought, but are you running the ac on full blast/low when trying to fill it?

[bluegill]

Just a thought, but are you running the ac on full blast/low when trying to fill it?

It was on full blast. I can't remember, but I think I tried incrementally turning up the AC when attempting a recharge once.

[bluegill]

well, I did not use a machine on my 96' nissan maxima, and it worked ( purge and fill with the autopart gas cans r22a). It worked for 5 years, then I sold the car in 2015, and still working!.

A4 b7 got a very simple ac system, it could work, but I wouldnt try it. few months ago I went for a refill, and it took about 45minutes- 1h. The machine purge the line, dry the line, and ajust the perfect qty and pressure.

at the end, if your b7 is a beater, try it with the r22a or r134a cans if your state allows it, and report. But my guess will be that youll have trouble with air.

If its not a beater, go to a proper place, and do it right the first time (100-150$ for a purge and refill).


the dryer got a big aluminum part at the top, if you're lucky, you can try to force the screws, but it might result of a leak. dryer are cheap, try to get a new one. also , it's very easy to change.

ac in winter is very useful to defrost and reduce hu% in the car.


Note : if you have a leak, it could be the pressure sensor on the condenser (driver side). The gas can leak through the connection pins. That was my trouble.

It holds a vacuum and everything. It just won't charge up past a certain point. Can't remember the exact pressure on the gauge from the last time I charged up, but it would reach that point and then wouldn't go higher, even with a new can.

[oVeRdOsE]

It holds a vacuum and everything. It just won't charge up past a certain point. Can't remember the exact pressure on the gauge from the last time I charged up, but it would reach that point and then wouldn't go higher, even with a new can.

so if I understand, you are trying to top-off the refrigerant?

is your can new?

heat it with domestic hot water, immerse it for 5-6 min. this should increase the pressure a bit.

I dont know the way to remove air from the system, but be sure you dont have any air... it wont react at the same of r134a, refrigerant can switch phase way easier than air...

[bluegill]

so if I understand, you are trying to top-off the refrigerant?

is your can new?

heat it with domestic hot water, immerse it for 5-6 min. this should increase the pressure a bit.

I dont know the way to remove air from the system, but be sure you dont have any air... it wont react at the same of r134a, refrigerant can switch phase way easier than air...

Not trying to top off the system. A hose was removed from the condenser so all the refrigerant escaped except the compressor.

The can(s) was new. I tried the boiling trick which did not work out.

I pulled a vacuum on the system and tested with manifold gauges. It held a good vacuum overnight with no loss in pressure. The problem is when I tried to add refrigerant. It will only take so much. The compressor does not kick on. Either the compressor is dead or a can doesn't provide enough pressure to get the compressor to turn on.

[a4lownslow]

If you haven't already you should be looking under the hood for the refrigerant capacity. Should be something like 500g or 18oz. I use a scale to weigh the can so you know exactly how much refrigerant is going into the system.

If you think the compressor is not engaging you should scan the hvac module for fault codes and check measuring values. You will be able to see if and why the compressor is being disabled. If everything is okay it's just a matter of adding refrigerant via a manifold gauge using low pressure side only. Can take a few minutes but you shouldn't have to do anything special.


Sent from my iPhone using Audizine

[4rings5stars]

I need to do this big time, too. Just found out after bering without AC for almost 2 years, as well, that one of the AC lines had a huge rupture in it!