With this recent cold snap (sorry, I mean Polar Vortex) having brought colder temperatures to much of the country, I have seen renewed debates online about the proper way to warm-up your vehicle in cold weather. There appear to be two sides to this debate - both of which make reasonable arguments:
1. Let the car warm up BEFORE driving. The reason being that engine oil becomes thick at cold temperatures and does not do a good job of lubricating the engine. Therefore driving the vehicle in this state creates extra heat, friction and wear-and-tear on engine components. In addition, other systems can be affected. For example, it is possible to blow out a power steering line if you drive off immediately in particularly cold weather without allowing the system to warm up.
2. Give the car 15-30 seconds for oil to start flowing, then DRIVE the car to help it warm up more quickly. Of course this does not mean you should go WOT and pin the tachometer. However, gentle driving helps that thick oil flow better, and gets it warmed up much more quickly. The argument here being that the increase in wear-and-tear you experience by revving an engine with cold oil is more than offset by the fact that the oil gets up to temperature faster, and therefore starts protecting the engine much more quickly.
Both arguments make sense. My quick Googling always seems to find more people favoring the second argument. I even went through the User Manual in my car (1998 Subaru Outback) and the only snippets of information I found are the following:
In the section describing the engine temperature gauge:
"We recommend that you drive moderately until the pointer of the temperature gauge reaches near the middle of the range. Engine operation is optimum with the engine coolant at this temperature range and high revving operation when the engine is not warmed up enough should be avoided."
In the section describing the steps for starting the vehicle:
6. Confirm that all warning and indicator lights have gone out after the engine has started. The fuel injection system automatically lowers the idle speed as the engine warms up. While the engine is warming up, make sure that the selector lever is at the "P" or "N" position and that the parking brake is applied
In the section giving tips for winter driving:
"While warming up the vehicle before driving, check that the accelerator pedal, brake pedal, and all other controls operate smoothly. Clear away ice and snow that has accumulated under the fenders to avoid making steering difficult. During severe winter driving, stop when and where it is safe to do so and check under the fenders periodically."
The user manual at no point actually references a specific time-frame for which you should allow the vehicle to warm up (or a certain temperature gauge reading), nor does it explicitly state "let the vehicle warm up before driving." It only states things you should do (do not leave the vehicle in gear, and, in the winter, check that the controls all work) while the vehicle warms up.
I am interested in starting a debate on this subject and seeing what the Jalop community thinks, and how they warm up their own vehicles!
EDIT: I suppose I should add that my personal view leans towards the second option. Also, in this debate we should exclude warming up the vehicle on days when you just want to get into a warm car. That is irrelevant to which is better for the car - sometimes you just don't feel like being cold!