Compressor life

[Cusser]

I have a question about AC compressor life in my 3 compact trucks; when the AC gets too cold, I've been switching off the AC using the push-in switch on the dash, and then pushing that back in turn the AC back on when it warms up. So my question is - for compressor life ONLY, not for gas mileage, etc. - would one get longer AC compressor life by doing this or by leaving the AC switch "always on" and adding some heated air with the selector?

The trucks are:
1988 Mazda B2200 with Sanden SD-708 compressor, still R-12, new compressor from ACkits.com installed in 2014
1998 Nissan Frontier with DKV14C compressor, R134a from factory; factory compressor with 273K miles
2004 Nissan Frontier with DKV14C compressor, new compressor/condenser/drier at about 100K miles

[Tim]

I've always said to turn it on once a month in the winter (Arizona ) for about 30 seconds to keep the seals oiled. Modern vehicles turn it on when the defrost is kicked in as well.

[bohica2xo]

Many of the carbon / ceramic seals in compressors over the years have been declared "bad" and replaced when they were just fine. The oil film on the seal IS the seal. Tecumseh and A6 seals needed to run to keep the oil film in place.

Running your compressor once a month or week should be enough. Running it all winter is overkill.

[Cusser]

No, no, no - that's not what I'm asking ! You both replied on how to keep a compressor "ready" during the winter.

I'm asking about summer driving, whether switching compressor off every few minutes or leaving compressor on full-time and blending in some heated air is better for long-term compressor life !

[bohica2xo]

With simple systems like yours, in the summer I leave the compressor on and control cabin temperature with fan speed. The frost protection device may cycle the clutch, or it may not.

Because of the constant cloud of marijuana smoke in traffic here in Las Vegas I keep the recirculate mode on all of the time.

[Tim]

No, no, no - that's not what I'm asking ! You both replied on how to keep a compressor "ready" during the winter.

I'm asking about summer driving, whether switching compressor off every few minutes or leaving compressor on full-time and blending in some heated air is better for long-term compressor life !

I would not think it would matter in the overall big picture. Plus, it would depend more on what type of compressor it was. Some are designed never to cycle. Adding heat depends on system design, airflow through evap or not. It may keep the compressor from cycling. Cycling too often tends to burn up clutches. I'd rely on the system design to cycle when they are supposed to.

[Tim]

Because of the constant cloud of marijuana smoke in traffic here in Las Vegas I keep the recirculate mode on all of the time.

Only after the cabin is full.