Every month CMS will be updating our 'Service Tips'- this month we talk about tips for cold weather operations of your BMW...
Cold Weather Tips for your BMW:
1. When you are going to first use your car, make sure your windows are clear, lights visible, etc.
2. Get in your vehicle and begin driving ASAP. The reason for doing this is that the engine will warm up much more quickly than if you were to just let it idle in the driveway. The reason for warming up the engine in the driving mode rather than than idling, is when an engine idles it will cause a lot of condensation to accumulate in the crankcase breather system. When that happens, your engine may perform fine that day, but when go through a major cool down, (ie, 10 degrees F and down to O degrees F and below), all of that water vapor along with the normal blow-by oil vapor that needs to be re-burned by the engine, (part of emission controls), is unable to, because the crankcase vent valve, hoses, etc will freeze. This in turn will cause oil consumption, uneven idling and when it can no longer breathe will cause the engine to leak oil severely or actually siphon oil out of the sump, causing the engine to hydrolock from oil ingestion- causing major engine damage in some cases. We have seen so much pressure develop that the valve cover will actually explode.
3. We can easily test for the ability of your car to breathe by testing with a Manometer, a device that measures vacuum. The tool has a column of water, which will pull water 3" to 6" when operating in the normal range. It is best checked on a cold morning, (car left overnight).
Another note for operating most engines: try to avoided starting your engine, only to move your car a few feet, (to let a friend out of the driveway, to clear the driveway, etc).
The reason for this, is the engine will not run long enough to warm the coolant, which when warm, sends a proper value to the coolant sensors, which in turn sends an electronic value to the engine management system, (computer or brain), which leans the mixture of the fuel needed. If the car doesn't run for long enough, the engine may not start the next time you try it, due to fuel being left on the spark plugs, or could cause a misfire, which will illuminate your check engine light.
(A sludged up crankcase vent valve, below.)