In the case of liquid-cooled engines it is also necessary to bring the coolant to working temperature to avoid the risks of shock-cooling parts of the block and heads with cold coolant.
Interesting observation. The Pilots Notes for aircraft equipped with Rolls Royce Merlins (Mustang and Lincoln for example, which I flew) in the Limitations section mentioned a minimum of 6o degrees C for coolant. I was never aware of the term "shock cooling" when I flew these types in the Fifties. The term is relatively more modern I believe.
From recollection (always a bit suss with age
) coolant temperatures would rise rapidly after engine start probably within one minute and so the 60C lower limit was not an issue. Probably because all of my experience on these aircraft was in the Australian tropics.
I am not sure if the point about shock cooling of RR Merlin cylinders is valid. My reading of WW2 history where RAF Spitfires and Hurricanes did "scramble" take-offs in Britain mid-winter soon after engine start, would suggest that shock cooling was not an issue for Rolls Royce Merlin liquid cooled engines.