is it necessary to let the Honda CRV turbo warm up and cool down for two minutes?
Did the owners manual say you must do this? If it doesn’t say you must do this, you don’t.
Yeah, I’d do what the owners manual says. I’d also drive gently on a real cold start, and I’d let it idle a bit after a high load drive (high speed, high temperature).
I wouldn’t worry about warming it up but it’s not a bad idea to let the engine idle for a minute or so before shutdown; especially if you’ve been driving it hard.
Over the years I’ve changed a number of failed turbocharges and without exception they all failed due to coked motor oil. Coked motor oil is essentially burnt motor oil that fries in the turbo oil passages due to heat.
Equally important is changing the oil more often on a turbocharged engine. Motor oil that accumulates higher mileages is more prone to heat breakdown; e.g. oil coking.
That, right there is why I started using synthetic oil in my first turbo car. Far more resistant to high oil temps. Modern turbos have water cooled ball bearings instead of the old sleeve bearings and are far less likely to coke up the bearing.
Can it still happen? Probably.
I agree that synthetic is less prone to the coking problem. One issue I’ve seen is that when the impeller bearings survive the oil coking may take place in the oil feel port and cut off or severely restrict the motor oil to the bearings.
That was one issue Subaru had with the coked up screen on the oil feed port.
However, if the OP is driving the car normally and not with their foot in it all the time I think they will be fine.
You do not need to idle the engine for a minute or two to warm it up before driving, but you should take it easy until the engine warms up and that applies to all vehicles, turbo or NA (naturally aspirated).
The only thing I would watch is if you are driving at high speeds, i.e. interstate and you need gas, pull into the right lane about a mile before the off ramp you intend to take for gas and slow down to 55-60 mph. That will cool the engine oil and the turbo down so the oil in the turbo bearing doesn’t get heat soaked while gassing up.
Most other end of trip shut downs usually involve some city streets or lower speed limit roads so the bearing and the oil will have cooled down enough to withstand the latent heat of shutdown.
Technically you don’t have to. But it’s really not a bad idea.