Because of water retention going from +30 Deg down to sub zero in less than 15mins.
But that's just a starter.
I am sure those that deal with these materials will have more of a clue. But "fairy liquid" dishwashing liquid of choice for mounting tractor and car tyres was banned 40 years ago in Aberdeen for oil work.
Alistair,
the use of "dish soap" is not allowed by the process specifications. some "genius" apparently decided that installing the seals was too difficult/time consuming and not meeting cycle time goals so they decided to just use dish soap to make it very slippery. its a non-compliance. probably not the only one in the factory.
They were using soap on the door seal, not hydraulic fittings. Soap reduces the freezing point.
It's clear that someone in QC should have flagged someone in QA who should have stopped the practice and flagged program management to get some engineers to do the research into whether this was an appropriate material or not.
'Dawn' dish soap is what they use to clean crude oil off the feathers of waterfowl after a tanker mishap or an oil spill in a wetlands area. It also works pretty good on your dishes and my wife uses it as hand soap in our kitchen (we have a dispenser installed next to the sink, which can be used to either dispense little soap when cleaning something or when you need to wash your hands).