I have a 2019 Smart Fortwo 453 Coupe. I ordered replacement spark plugs and the tools listed as suitable for it from Autodoc, but I've been putting the job off for three or four months.
The reason probably sounds silly: I read, or ChatGPT told me, that the car has to stand for at least 24 hours before changing the plugs. I use it every day, so finding a full day when I don't need to drive has kept me from getting started.
I want to check whether that advice is actually correct for this car. Does it really need a fixed 24-hour wait, or does the engine just need to be completely cold? Could I drive home in the evening, park it overnight, and change them the next morning before starting the engine? How do you judge when it's sufficiently cooled down?
I'd particularly appreciate experience from someone who's serviced a petrol 453, or a reference to the manufacturer's procedure. Are there model-specific reasons for waiting that long? I'm asking about the cooling requirement, not looking for permission to remove plugs from a hot engine or skip the proper procedure.
I haven't specified the exact engine variant, mileage or transmission here, so please flag if those details change the answer. I don't want to guess specifications. I've also asked in AskMechanics for a second opinion. Thanks!