Proper Engine Warmup Procedures
- Category: Safety & Driving
By Bud Osbourne
The reason that engineers recommended the "drive away" warm-up, as opposed to allowing the engine to warm up at idle was that the faster the warm-up, the lower the build up of harmful condensation within the engine and exhaust systems. So, if you are only going to drive a short distance, you (your car's engine, actually) are better off just driving away after a very brief (30 seconds or so) warm-up, thereby allowing the engine to warm up quickly, and minimize the amount of harmful or corrosive condensation build-up, before shutting down. The majority of the engine wear occurs immediately upon start-up, no matter whether you drive right away or sit and warm it up.
Your engine will incur less frictional wear if you let it warm up at idle (at as low an rpm as it will run at) than if you just drive away. However, if you slowly warm it up at idle and then drive only a short distance before shutting down, the condensation formed in the crankcase (which didn't get a chance to evaporate/boil-off during the short drive) will then work it's mischief. This is the main reason that more frequent oil changes are recommended, by manufacturers, during cold weather months; to get rid of that condensation.
So, if you want to "drive right away", not only should you keep the revs down (but avoid lugging, at all cost), but you should keep the engine load / throttle opening very light. If you drive a cold engine, right away, under high load / high throttle settings, your engine will wear very rapidly indeed.
A "static" warm up is good, provided you are going to drive the car long enough for the condensation to evaporate / boil-off, before reaching your destination. Personally, on my 356, I use a combination of the two. I let it warm up, at idle, for a few minutes at as close to 1000rpm as I can manage (usually it's between 1200-1500), then drive away very gently for the first several miles, until the oil temp gauge clears the left green "spot". Of course, I live in a rural area, where I can do this without getting in everyone's way. Those of you in built-up areas, with lots of traffic, probably won't have the luxury of allowing the engine to come up to operating temperature, before you might need to use a heavy application of power. In other words, no one's situation will be exactly alike, so, we all need to do what suits our car's needs vs. traffic and weather conditions to keep engine wear to a minimum.