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Wed Jan 31, 2018 7:15 pm

Hello all,
I'm in the final stages of my SC in-dash A/C install. I've been searching for info on how to choose my oil and refrigerant for the system. I've mainly found youtube videos of guys recharging their systems. I've read that the oil choice should be determined by the compressor and what the manufacture recommends. I also see the different refrigerant options. I ask on fellow van owner and he said R-134 so that seems to be the route I'll go.
All of my system will be new so there is no previous oil or refrigerant in the system. I'm still searching and reading what I find but can anyone give advice or an opinion on this topic.
Thanks GreggK

Wed Jan 31, 2018 8:49 pm

http://www.aa1car.com/library/pagoil.htm

Keep cool! 8)

- Dave

PS: Certainly go with r134a if you expect a shop may ever work on your AC, but
be aware you will take a hit in performance compared to r12a. If you're willing to
do your own work using r12a you will get better bang for your buck but then you
must never expect any run-of-the-mill AC shop to touch it...just sayin'...

<shrug>

Wed Jan 31, 2018 9:05 pm

Greggk

Which compressor do you have?

Wed Jan 31, 2018 9:06 pm

Looks like I can find some useful information on that link. I just too a look. I'll have to go look at my compressor to see who the manufacture is. I appreciate the help.

Thu Feb 01, 2018 3:00 pm

I suggest that you use PAG oil and, for the viscosity choice, go with the viscosity recommended by the compressor manufacturer.

PAG works with both R134A and also with Red Tek. In fact, if you use RedTek and later decide on a servicing or a sale that you want to use R134A, you can release the Red Tek to atmosphere (it is a hydrocarbon, not an ozone-killer), vacuum down the system, and install R134A refrigerant.

I have had an excellent experience with Red Tek and highly recommend it. The key aspects of its superiority to R134A are lower head pressures on the high side of the system, and better cooling performance.

FWIW, I used PAG 100 for my Subaru SVX compressor, but each compressor has its own recommended viscosity. Note that the SVX compressor is very different from the compressors found on the 2.2 and 2.5 Subaru engines.

Thu Feb 01, 2018 4:34 pm

Here is a nice gotcha for AC first timers

There are a couple major kinds of PAG oil , so called PAG100 and PAG46 and PAG150

There are others, but those are common.

ZEXEL, a major manufacturer of AC compressors, also makes PAG oil.

They make a product called ZXL 100PG - which is made to PAG 46 specifications.

Seriously.

Thu Feb 01, 2018 9:13 pm

Thanks for all the replies. I'll check on my compressor as soon as I get a chance. Work has taken over once again. I wont even have time this weekend to work on my van!

Thu Feb 01, 2018 9:27 pm

PAG100 and redtek.

Wed Feb 21, 2018 7:34 pm

I've finally got the time to update. I'm pretty sure the name on my compressor is "NEW". Its made in China and actually has the recommended type of refrigerant and oil printed on a label. Soon I'll run all the hoses and button it all up.
Is it recommended to have a shop charge the system? I don't really let anyone work on my van aside from alignment, which I don't think even gets done properly. I see there is some specific equipment for this. Any opinions?

Wed Feb 21, 2018 7:57 pm

You need a vacuum pump to evacuate and leak test before you charge.

Then you need to study up for a couple of weeks to understand the process

If you go in unarmed with knowledge you. Have about a 90% chance of screwing it up

Wed Feb 21, 2018 8:07 pm

I Have been researching a little about the procedure. Mainly what I have found on youtube. So far I feel I should be able to figure it out. A/C systems are new to me as is my entire engine. Also my first diesel. Did the install myself. I like to understand all the systems in my van.

Wed Feb 21, 2018 8:09 pm

A licensed shop will typically refuse to fill with RedTek which is, in fact, far more efficient refrigerant in the Vanagon application than R134A.

If you have or borrow a set of AC gauges and an AC service vacuum pump, then you can do it yourself.

I wrote a step-by-step how-to some time ago intended to help those who are handy, but have no AC experience. Have a look in this long thread at page 49 of the thread:

https://www.thesamba.com/vw/forum/viewtopic.php?t=...;start=960

Wed Feb 21, 2018 8:26 pm

I'll get on that. Thanks for the information!

Thu Feb 22, 2018 5:12 pm

So if you fill with RedTek you can go back and refill with R134a. What if you start with R134a can you switch to RedTek if you evacuate the R134a properly?
The stamp on my compressor calls for R134a and PAG46 oil.

Thu Feb 22, 2018 5:39 pm

Your compressor doesn't care what refrigerant is used, but you want to keep the same oil as was filled in it at the factory, though you can always flush and refill with a different oil. I believe PAG oils are hygroscopic, so I'm not a fan. If you're going to use a hydrocarbon refrigerant like RedTek then to me it makes sense to just use a mineral oil, but that's of course just me.

Fri Feb 23, 2018 7:30 am

Zeitgeist 13 wrote: Your compressor doesn't care what refrigerant is used, but you want to keep the same oil as was filled in it at the factory, though you can always flush and refill with a different oil. I believe PAG oils are hygroscopic, so I'm not a fan. If you're going to use a hydrocarbon refrigerant like RedTek then to me it makes sense to just use a mineral oil, but that's of course just me.

They arent as bad as brake fluid for mopping up water, but if you are getting water into your AC system you are f*d for other reasons. Once you pull the vacuum and load the choice of poison, the system will sit at at about 2 bar pressure even in winter....no water should make its way in at all.

I pump mine down for about 4 hours, then let it sit under vacuum overnight and confirm its holding vacuum before charging. If not, find and fix leak.

My newest car is an 2006, all hold an AC charge for >4 years without needing a top off.

Fri Feb 23, 2018 8:05 am

I think the hygroscopic issue is with older leaky R12 systems sloppily converted to R134a and then just topped up when they leak out, which leads to internal corrosion problems due to atmospheric intrusion. The R134a system in our '94 Audi has never been opened or topped up. I don't mess with inoperable AC without first seeing if it will hold vacuum overnight, but that's not how most DIY types approach the problem.

Tue Jun 19, 2018 1:31 pm

OK to mix PAG oil with the original R12 mineral oil when charging with RedTek?

Tue Jun 19, 2018 2:40 pm

My understanding is NO, PAG oil doesn't mix well with Mineral oil. in the circumstance, you use ester

Tue Jun 19, 2018 3:07 pm

So Ester and the old mineral oil are OK to mix with RedTek. I'm skipping the compressor removal/oil change until next summer, but my compressor oil level reads low. I installed a new receiver/dryer and I assume that has some oil in it.