Leaving it idle

[fatcatsailor]

Simple question from a newbie..can't find the answer in the forum. In my owners manual is says it's better to drive you car slow as it warms up than to let it sit and idle. I live in MN and a cold car is not fun. Has anyone heard of this? Is there something I don't know about my e39? Got and auto trans. The one with no dip stick lol
Thanks for a fun site

[Lord Vader]

I live in Canada so I know all about cold. What you said is correct as stated in the owners manual. The reccomended idling time is about 30-60 seconds. The engine is comprised of different metals which all warm up at different temperatures. Driving the car is the best way to warm up all the different metals at the same time. When metal cools or heats up it expands and contracts, and in an engine it's not a good idea to have components expanding or contracting to often.

[fatcatsailor]

Thanks Vader, after it is already warmed up it don't hurt though right. Can't see shutting it off in a traffic jam or to run into a store quick right? American made cars are made of different metals to in the engine, this is very different.

[Lord Vader]

Once it's warmed up it's fine to shut off to run into a store. It's the initial warmig up thats important. You don't want moisture to form in the exhaust and rust or freeze so it's important to get it up to normal operating temp.