evacuate AC - replace PAG oil?

[slapshotjh]

When the ac is pulled under vacuum to evacuate the system, does the PAG oil have to be replaced? I am not sure if the oil gets sucked out as well?

The car is a 97 B4V conversion. Just getting around to trying to get the AC to work.

 

[Redlabel6]

Pulling a vacuum will not remove the oil. Most of the time unless you replace your compressor or accumulator you should not need to add oil.

 

[slapshotjh]

I am only replacing the condenser and the dryer/accumulator. How much oil is needed if the accumulator is replaced? And do I just pour new oil into the new accumulator? Or does it get poured into one of the lines?

 

[TonyJetta]

I'll look when I get home later tonight: IIRC, ~1oz in the drier and ~1oz in the condenser.

You can add oil (PAG46) directly to the components, or pick up a 1-2oz freon/oil charge for when you recharge it.

Tony

 

[slapshotjh]

Ok I replaced the condenser and the dryer. Put an ounce of oil in the dryer. Replaced the o-rings. It won't hold a vacuum, so I bought o-rings for the compressor and put them in. Still won't hold a vacuum.

I decided to try the dye. Put a small bottle of freon in. The fan kicked on, and the ac clutch engaged. Once the bottle was in the system. I disconnected the gauges and was getting ready to put a shot of the dye in the low side, when the high side connector popped and started letting out freon.

Does this mean that my expansion valve is blocked? I have been able to send compressed air thru the system low to high, but not sure if that tells me the expansion valve is working. I could hear something in the ac system click when I shot compressed air in there, and I assumed it was the expansion valve opening.

 

[gquenstedt]

freon is coming out of the high side service port where you would connect a gauge? I'm pretty sure that shouldn't happen regardless of the pressures inside the system.

Maybe there is debris that is not allowing the valve to close all the way, or maybe you need a new valve, in which case might have to replace the line that the valve is part of.

I could be totally wrong though... I've done a little A/C work with mixed results

 

[TonyJetta]

Not sure, sometimes expansion valves need a little kick to initially start working. Tap with a hammer or momentary high pressure.

Momentary high pressure can be dangerous. Try at your own risk!

One tip for the o-rings: use a product called NYLOG. It's a freon compatible sealant, and it's also sticky to keep the o-rings in place.

I'm not sure how long your system was out of service or exposed to the elements. The expansion valve may need to be replaced.

On an expansion valve system, and the compressor is replaced, the expansion valve is usually replaced with the compressor.

I would also replace the hi side pressure port; Autozone should be able to supply a generic port service kit.

Tony

 

[slapshotjh]

Not sure, sometimes expansion valves need a little kick to initially start working. Tap with a hammer or momentary high pressure.


I would also replace the hi side pressure port; Autozone should be able to supply a generic port service kit.

Tony

Glad to hear that can be done. I was freaking out when I discovered that the rubber gasket/seal or whatever it is inside the service port came out. So the port itself is leaking. Do they unthread? I see where you can get a wrench on it. Looks pretty flimsy sitting there on that high pressure line. With my luck I will bust that line.

I think I will start with the service port, as that is leaking pretty good now.

 

[ninedee_golf_tdi]

It's a shrader valve, but made for a/c systems. Most auto shops should carry a replacement.

 

[zeumer]

no, no. you don't unscrew the valve. you unscrew the guts of the valve, takes a special tool but cheap, sometimes a tire dust cap has one.

 

[slapshotjh]

Boy, it sure didn't look like a tire schraeder valve in there. Looking down from the top I saw a brass colored flat piece of metal fitting across the entire diameter of the hole. I will stop by autozone on my way home from work and see what they have.

I have noticed that the after putting the red cap back on the high pressure port, its seems to be holding pressure. There was still some (not nearly enough and not evacuated first, freon in it. The switch the tells the compressor and fans to kick in is sensing enough pressure in the system.

 

[TonyJetta]

Not sure about this: VW might sell a service port kit. You would need to talk to a knowledgable parts guy, or someone on the club site might know.

Tony

 

[slapshotjh]

From searching online, it appears that when the high side service port does not have a schraeder valve in it, that the whole port must be replaced. The online images for autozone's high and low service port repair kit shows two caps, two schraeder valves and a schraeder valve tool.

My high side service port doesn't have a schraeder valve. I called the local vw dealer and the high side service port/vlave is just under 40 bucks.

I guess I will try to remove the service port carefully before I order it. If its galled on there, I am guessing the high side line will twist when I put a wrench on it.

 

[tripl-e]

From searching online, it appears that when the high side service port does not have a schraeder valve in it, that the whole port must be replaced. The online images for autozone's high and low service port repair kit shows two caps, two schraeder valves and a schraeder valve tool.

My high side service port doesn't have a schraeder valve. I called the local vw dealer and the high side service port/vlave is just under 40 bucks.

I guess I will try to remove the service port carefully before I order it. If its galled on there, I am guessing the high side line will twist when I put a wrench on it.

I bought generic quick disconnect adapters for my gauge set and they came with one new high pressure port. It must be routine to replace these things.

 

[slapshotjh]

I wound up replacing the whole line. I could not find a way to fix the high pressure service valve. It was not a schraeder valve on my car, and the dealer said to replace the whole line. I bought a used one on vortex. Evacced last night, and it seemed to hold vacuum. So I put two of the little cans in it. It was blowing cool, but not cold air. Pressures were coming up. Decided not to put the third can in, and just run it a trip or two to see if it holds this charge. If I truly have no leaks I'll go ahead and finish the job.

 

[dieselherb1]

I have a 97 Passat, replaced Alt. noticed the pulley on the A/C comp. wobbling. So I have a donor car I toke the comp. off(cooling seconds before I took it off, I checked) and installed it on the 97. added freon clutch seems to work but not even cool air. So now I need to get it working I take the A/C comp. off my car another 97. A/C working good as I drove it on to the lift. Put that comp. on the other 97, installed freon(2 cans) not even cool. Both cars had working A/C minutes before removing comp. Help!