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Comment by Frye9876 | Hacker News Reader

Yes. Almost the entirety of engine wear occurs when the oil temp is too cold. By turning on the vehicle and immediately driving (conservatively below 2k rpms) you greatly reduce the amount of time it takes to warm up your engine oil versus when left idling at 500rpms. I learned this from reading the manual to my BMW and Subaru.

In -20 degree weather you won't accomplish much idling and should purchase an engine block heater if concerned.

Interesting article confirming what I am saying:

https://www.washingtonpost.com/news/wonk/wp/2014/12/29/the-b...

View on HN

I don't doubt you, but I know for a fact that by turning on my car and waiting inside I could get in and the car was warm. No waiting. Did this for twenty years.

You two are talking about different things. Frye is talking about warming the engine compartment; Epic is talking about warming the passenger space. You can warm the engine compartment more efficiently without idling by driving at low RPMs for the first few minutes; however, idling is as (or almost as) effective as low-speeding driving at warming the passenger area.

>however, idling is as (or almost as) effective as low-speeding driving at warming the passenger area.

Again, twenty years of turning the car on, going inside for 15 mins, and coming out and sliding into a warm car.

I'm not anywhere near knowledgeable enough to explain the details. I am fairly certain however that I was not hallucinating this throughout my entire childhood and young adult years.

> however, idling is as (or almost as) effective as low-speeding driving at warming the passenger area

No. The engine, and thus the water, will heat faster under a driving load.

The other advantage of idling is that when the windscreen is misted up, it doesn't matter that you can't see through it!

You can wipe condensation off, but I've always found it has a tendency to reappear quickly. Perhaps I'm wiping wrongly, but the only solution I ever found to work reliably is to leave the aircon and windscreen heater running until the inside of the windscreen has warmed enough to prevent immediate reoccurrence.

That's meant idling the engine in every car I've owned. Cabin heating never seems to run at full blast unless the engine is powering it...

Terrible pro tip: get in the car, start it, immediately start driving, but floor the accelerator and use the brake to travel at the speed you want. You'll have a warm passenger compartment in 1-2 minutes.

It's absolute hell on the engine though. Don't do this with vehicles that you are responsible for. This is mostly only applicable for leased vehicles.

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