it's really no difference than driving around town or driving down the interstate for 40 minutes as long as the cooling fans are working correctly and it's not running hot.
It is also advised to keep this practice to a minimum - it’s just more wear and tear on the engine and related components that’s really not necessary.
Cooling fan operation is critical; as the others mentioned -- should be of little concern. Transmission fluid must continue to be cooled also, as it tends to get extremely hot just idling. This is also where the cooling fans help.
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It is also advised to keep this practice to a minimum - it’s just more wear and tear on the engine and related components that’s really not necessary.