Recharging A/C - add oil?

[jb20thae]

I purchased a 91 recently whose AC was converted to r134a ("new compressor, discharge/liquid line, build up ac hose assy, evactuation" according to service records). The system does not blow cold and I was told by PO that it just needs a recharge. Can I safely try recharging with a diy recharge kit or is there an oiling that needs to happen too? Are the additives in AC PRO safe for our systems?:

https://www.homedepot.com/p/AC-Pro-20-oz-Professio.../207170014

[djkeev]

Before jumping into the just add refrigerant cart, you really need to see what is happening with your A/C.

I'm guessing the interior fans at the rear work?

With the engine off but key on, when you rotate the "snow flake" knob clockwise do you hear a click at the compressor?
Maybe get a friend to turn the knob as you watch ad listen.

No click?
You might need refrigerant..... but where did it go? How did it get out?
How much is still in there?
A violent rushed exit of gas takes oil out with it. A slow leak generally does not take much at all.

The 91 came with r134a ...... there was no converting to it.

EDIT: I remember reading this ^ somewhere but cannot verify is tfuth, o take if with a grain of salt, it isn't important anyway.......

You really need to hook up gauges and see if there is any gas pressure in your system.
Over charging a system isn't good.
If the gauges show zero pressure, you need to get an evacuation pump and pump the system down to a negative vacuum.
Any air in the system contains moisture, any moisture in the system can freeze in critical areas while the system operates blocking the flow of gases.
Once at a vacuum you can shut off the pump, observe the gauge readings and wait a day and see if it holds a vacuum over night.
If the gauge shows a loss of vacuum, you have a leak you need to locate and repair.
There are several threads here on rebuilding and charging A/C systems.

I'm not an additive kind of guy...... if it leaks...... find out where it leaks and fix it!
Stop leak products do no good in the long term.

Find out what is happening right now and proceed from there.

Non functioning A/C can have multiple causes, only one of which requires more refrigerant.

This vintage Of A/C is having an increase in the number of over heating electrics in the A/C control panel in the left rear pillar.

Dave
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[T3 Pilot]

Always do what the PO said. The little Hippy girl that I bought my Syncro from told me that she carried the battery boost pack around “cause sometimes (insert sappy anthropomorphized name of Van here) just needs a little help to start in the morning”

Yeah I need a little help to get started too, usually a coffee. In any case I found it simpler to repair the broken alt exciter wire.

This is the long way of telling you that you need to find the leak in your A/C system and repair it.
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1988 Vanagon

The most important part in every vehicle is the nut behind the wheel......

[Abscate]

The statement “ it just needs a charge” or “ it jusyt needs a can of refrigerant each summer” should have a $10,000 fine attached

$5000 to go to the one who turns them in, like Texas does.
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The capacity of the vanagon AC is 47.6oz. When you turn the AC ON, look at the compressor clutch . If it's not engaging then you can't charge it.

Here's a trick. With the engine off, disconnect the white connector on the top of the compressor, connect one wire to the ground and the other wire to the pos(+) on the back of the alternator with a pair of jumpers.. If you hear a loud clack that means your compressor is good, the clutch is working. Now you can run the engine and start charging the AC, half way through the charging, disconnect the jumpers and reconnect the white connector and continue charging the compressor.

[jb20thae]

Excellent condensed info to work with, thanks. I have total respect for the PO and their knowledge of autos. He spent 1000s getting the AC operational. I’m surprised to hear the 91s were already 134, first I’ve come across that. The “m” code or whatever should tell me what options the van was confirmed with, yes?

[djkeev]

If you can locate your M codes,
They were applied to a paper sticker below the fuse box.
Most are long long gone.

Look at your compressor it should say r 134a on it.

BTW don't go jumping the A/C clutch without doing any leak diagnosis or evacuating of the system and just blindly put refrigerant in.
There are reason why the clutch doesn't engage...... you need to find that reason and fix it.

But your Van, do as you wish.

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[sjbartnik]

[djkeev]

[Howesight]

R-134A refrigerant eats ozone in the ozone layer, requiring our sunblock layer to be thicker and reapplied more often. Declining ozone increases skin cancer risk as well as other environmental damage. Dupont did no favours for us when inventing R-12 and R-134A.

Having vented my spleen above, all Sambanites should note that the hydrocarbon-based refrigerants like Red-Tek and other refined butane-based analogs WILL NOT eat ozone when (not if) your leaky Vanagon AC system vents itself empty. In addition, the Red-Tek type refrigerants perform better than R134A because Red-Tek operates at lower head pressures, thus putting less strain on your compressor. It also has a large molecular size, which is a benefit because it will not leak through the factory VW hoses. The original refrigerant, R-12, also had large molecular size and the low-tech VW factory rubber hoses were not permeable to R-12. R-134A has a very small molecular size and can permeate through old rubber AC hose rather quickly, calling for annual (or worse) "top up".

Honestly, there is no down side to using Red-Tek and I strongly recommend it. Dupont has seen to it that certified auto AC techs are deeply afraid of installing RedTek in customer cars since it is, admittedly, more capable of ignition in case of a catastrophic accident breaching the AC system. But the amount of refrigerant in the Vanagon AC system, IF you could create the conditions necessary for it to burn (a proper fuel/air mixture) is so small, compared to a half-tank of gasoline, that the risk of a RedTek inferno is basically nil.

Regarding what to do now, I would suggest that you buy or rent a "hobbyist grade" AC vacuum pump and gauge set, evacuate the system and find the leak(s). If the previous owner only replaced some of the hoses, then first remove and rebuild the ones that were not replaced with modern barrier AC hose. Any Parker Hose outlet can do this for you. Use all new O-rings on reassembly, being sure to lubricate each O-ring with PAG oil when installing. Not doing so is a rookie mistake I learnt the hard way.

When installing the RedTek, if your system is vacuumed down to 29 inches of mercury, (with no leaks), then you can install the first canister of RedTek as a liquid, with the engine and compressor off. To install refrigerant as a liquid, you simply position the outlet of the canister down, in which case the vacuum in the AC system, plus the pressure in the canister, causes all the contents to go into your system as a liquid and far more quickly than it would as a vapour.

Usually, the one can of RedTek will be sufficient to cause the refrigerant low-pressure switch to power on the compressor. If not, you can jumper the low pressure switch connector to engage the compressor clutch. Now add more Red Tek as a vapour, with the canister outlet oriented UP, installing through the low-pressure service port. Make sure your gauge set is not opened on the high-side or else high-pressure vapour will flow into your can of Red-Tek and may cause it to explode from over-pressure. Most Vanagons seem to be happy with 3 cans of Red-Tek in total, plus or minus. The key finishing step is to adjust the amount in the system to achieve lowest AC vent temperatures. Use a $20 AC vent thermometer for this measurement.

If you don't know how automotive AC gauge sets work, read up on it. In a nutshell, when the low-side hose and high-side gauge hoses are properly connected to the service ports, the gauge set will read the refrigerant pressure at each port, regardless whether the high-side/low side gauge-set valves are open or closed. Some folks mistakenly think that these valves need to be open to measure pressures. Not so. The gauge set valves, when open, only open a path between whichever valve is opened, and the center hose, which on most gauge sets is yellow). The yellow hose is connected either to your vacuum pump, or to a canister of refrigerant.

Regarding oil, if the source of the refrigerant leak appears to have a lot of leaked oil around it, then it may be a good idea to add some PAG oil. A slow/small refrigerant leak will often carry very little oil out of the system, but a fast leak, when oil is still suspended in the refrigerant, will leak a lot of oil out of the system. Try to determine which viscosity was added previously and use the same viscosity. The late ('86 and later) Vanagon AC system, IIRC, specified 8 fluid ounces of oil. If your system had only a very small leak and there is little to no evidence of oil having leaked out, then adding, say, one fluid ounce would more than account for leaked oil. To get the factory spec exact would call for a full flush and draining the compressor itself and replacing all 8 fluid ounces. If you over-fill the system with oil, no damage will occur, but cooling efficiency decreases as the oil layer interrupts heat transfer in the evaporator and the condenser.
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'86 Syncro Westy SVX

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