"Old wives' tale"
Yes, there is an "old wives' tale" stating that if you lay a fridge down on its side, you have to stand it upright and wait some oddly specific and excessively long time period before starting it up.
People come up with these trying to explain things when they don't have the technical background to understand it. They have seen or been told about certain things and they piece together bits of unrelated info; resulting in this sort of belief developing. What actually happened is, people didn't follow proper transportation procedures which were required for some of the very early refrigerator designs. Because of this, there was actual damage done while the fridge was being transported. The damage happened due to bouncing and jouncing without the compressor properly secured, but the people didn't notice this - they only noticed that the fridge didn't work after it was relocated.
General Electric was one of the first to successfully sell domestic refrigerators. Their earlier models had oil heaters which needed to preheat the compressor sump before startup. The GE manuals caution against starting the compressor before the fridge has been plugged in and the heater has had time to warm the oil.
How all this got mish-mashed together in people's collective minds I can't answer. However, it seems to be the most likely way this came about.
Technically, the reason for transport instructions has to do with compressor suspension designs. Many earlier designs had the compressor sitting on, or hanging from springs. This prevented vibration from transferring to the fridge cabinet and making noise. The manufacturer provided shipping hardware to lock the compressor down solidly for transport. On Frigidaire it is often a pair of bolts which will fully compress the springs and solidly bind the compressor. On Coldspot it's either similar two bolts, or there are three points to install additional bolts to attach the compressor to the framework. General Electric provided latches on some of their models which would do the same. If these devices weren't used, the compressor could bounce around violently and break the refrigerant lines or wiring.
As a repair person, I have fixed many fridges which came in with this story. All of them (as in 100%) had leaks which caused them to stop working. Not all the leaks were around an unsecured compressor, but they had all developed leaks somehow. No amount of standing upright would have corrected this.
Another concern is weak evaporators. As long as the system is operating, the evaporator operates at slight vacuum to maybe 10 PSI depending on model. When the system is off and fully equalized, it may have 50, 75, even over 100 PSI depending on ambient temperature. If you have a corroded or frost bulged aluminum evaporator which has been in operation for decades without seeing high pressure, it may just start leaking once the system equalizes. That sounds hard to believe, but I have had a few which did just that.
So, people will have a fridge which works. The then transport it and now it doesn't work. They know nothing about how the fridge is assembled nor the proper transport procedure (if any). They are grasping at straws as to why and came up with this superstition or wives' tale.
As for why it doesn't matter with more modern compressors, this is very simple. The compressor is bolted to the fridge cabinet with hardware and some small rubber grommets. There is little if any movement to stress and bend and break the lines. So you don't have to do anything special with the mountings before transporting it.
The pictures attached are the result of improper transportation procedures. The grey compressor is a Coldspot which literally fell off its springs during transit, breaking a line. The other one is a Frigidaire which had the springs broken off on one side, and the discharge line snapped. But you know - if they had left the fridge upright for 24 hours before startup, this would not have been an issue!
Sincerely,
David
