Running AC In Winter To Lubricate?

[OK-944]

My 944’s owners manual recommends running the AC system briefly at least once per month over the winter to keep it properly lubricated.

While this make sense, I’m also wondering (especially here in northern Vermont) if there are any possible downsides of running the system in cold temperatures, and/or if there are specific ambient temps below which might possibly cause harm to the AC system?

Also...are there any special "tricks" to running the AC in cold ambient temps - like setting the heat up while doing this?

[v2rocket_aka944]

Yes it's a good idea to run the AC once a month or so to keep everything lubed up. This is still in modern car manuals, and also a good idea for your house AC too.

No, the components of the car aren't going to care if it's deep winter where you live.
R134 has a boiling point somewhere around -15F and I don't think you'll be running your 944 below that

[kuehl]

I wonder if the compressor engages in the defrost mode.

[OK-944]

I've wondered about this also. It would be nice to think that by pressing the defrost button the AC circuit would be engaged (which also helps to dry the incoming air, making defrosting more effective), as in more modern systems...with the added benefit that this helps to keep the AC system healthy.

[kuehl]

Yeah. So I'm pondering what does not get 'lubricated' and what are the proven consequences. Hoses do not have to lubricated. Old buna or nitrile, and now HNBR rubber compounds do not need to be lubricated. The compressors do not have sumps. At what time frame does the oil 'evaporate'? off the piston, wobble plate, or bearings?
And, if so, I've never run my HVAC system on my condo's or homes for at least 9 months out of the year. Yeah... so I'm pondering.

I remember when cork gaskets were used on valve covers!

[djnolan]

What about the shaft seal? Not that it necessarily needs oil, except to limit the freon leaks around it.

[Dano944]

Speaking of A/C, do our old 944’s run R134 or the old R12 refrigerant? I’m still on a crash course to learn everything about my ‘83 944 since my father-in-law passed and I know nothing.

[boom10ful]

I've seen the aftermath of leaving a fleet to sit without running the AC system for a few months. Lots and lots of shaft seal leaks. I can confirm that at least on the S2 with defrost mode on it does engage the AC compressor.