Warming Up Your Car in the Cold Just Harms the Engine

[93Regina]

The long-held notion that you should let your car idle in the cold is only true for carbureted engines.

In the thick of winter, the common wisdom is that when you are gearing up to take your truck out in the cold and snow, you should step outside, start up your engine, and let it idle to warm up. But contrary to popular belief, this does not prolong the life of your engine; in fact, it decreases it by stripping oil away from the engine's cylinders and pistons.

In a nutshell, an internal combustion engine works by using pistons to compress a mixture of air and vaporized fuel within a cylinder. The compressed mixture is then ignited to create a combustion event—a little controlled explosion that powers the engine

[jimmy57]

The engine management system for 25 years had speedy warm up strategies. All engine redesigns have reduced coolant quantity in block and heads. The emissions testing includes cold starts and the car makers had to reduce the length of time the fuel mixture was enriched and speed up catalyst and oxygen sensor warming to get those online quicker.
The problem is these strategies are not nearly as effective when engine is idling. They work VERY well if you load engine and drive off gently.
The belief that the metal needed to expand and exhaust manifolds will crack if you didn't allow warm up maybe was never 100% true but certainly is not true for welded stainless pipe manifolds or for engines where there is no manifold and pipe attaches direct to head (Some GM v6, Ford 2.3 ecoboost 4 and 2.7 ecoboost v6, Volvo 3 cylinder Drive-E).
The electric water pump engines have even more tricks for quick warm up other than retarded ignition timing and manipulated camshaft positions.

[93Regina]

They work VERY well if you load engine and drive off gently.

With commercial EFI diesel engines (aka semi-truck type engines), by early 1990s, drivers were being informed to start engine, then wait until air pressure was at operating range, and then gently drive off until engine was around normal operating temperature...then full power was OK. Also, drivers were being told to reduce idling time by turning off engine if more than say 5-20 minutes for a stop; nowdays, many over the road trucks have auxiliary power units to run when truck is parked.

With carbureted engines, since gasoline was bypassing rings and mixing with oil, this was one reason these carbureted engines didn't last as long before overhaul, especially those vehicles driven short miles. Engine heat will evaporate gasoline/moisture in oil if engine runs long enough.