And what would be the shortest ideal commute?
In David’s article from this morning, the focus is mainly directed towards how long a car should idle before driving it on the road.
It’s an important question for those who care about engine longevity, with what I consider to be a well-reasoned answer. However, there are more levels of “warming up” an engine to discuss, perhaps more than ought to be jammed into one article. After an engine is warm enough to (gently) drive, there eventually comes a point at which it’s warm enough to start getting heat from the heater core, and another point at which it’s ready for the driver to stomp on it. But how long does it actually take to satisfy every last part of the engine and fulfill a complete heat cycle, after which you can shut it off with zero risk of “short tripping” the engine?
If I’m not mistaken, the final goal would probably be to reach the point where all condensation in the engine has had a chance to evaporate. Condensation in the crankcase, under the valve cover(s), in the PCV system, that sort of thing.
So what would the perfect commute look like? After a few seconds (or a minutes or two in cold weather) of idling, what would be shortest, most mechanically-friendly drive cycle? Would it be something like 5 minutes of gentle 25mph residential streets, followed by 5 minutes of moderate 50 mph highway, followed by 5 minutes of 75 mph freeway running, followed by 5 more minutes of city driving to your destination? Just some nice round numbers to get the discussion started.
Obviously the answer isn’t going to be something that’s practical for everyone to apply religiously. I know that as gentle as I might want to be on my cold engine, I live too close to a 55mph road to spend much time getting up to speed. (FWIW, I try to keep engine speed below 2000 RPM until it’s warmed up a bit more, but that’s not really an option for some cars. Depends on engine output at a given RPM, and of course gearing.)
And I’m sure there are many more variables that have an effect. Like engine speed, engine load, the presence or absence of auxiliary oil coolers, stuff like that. What comes to mind?
Does your car have an oil temp gauge? Mine don’t. What do you usually see? When does the oil come up to temperature in relation to water temp, and how much further beyond that do you consider the engine to be 100% warmed up?