How long can you idle a car for?

[thexav]

I know you shouldn't idle a car but why?

How long is it ok to leave a car idling for? What damage is likely to happen if you do it too much?

How are you supposed to warm up the engine in winter time?

 

[Lunchmoney]

I know you shouldn't idle a car....

Never heard this. Beyond the waste of fuel, I can't see a problem.

 

[TCJBOLDIE]

I only let it idle on start up wile I get belted up and all the instrument panel has done its thing and check if all the warning lights are off then drive sensibly till the fluid gauges are at the normal positions before any hi rev hard acceleration. It's called "mechanical sympathy "

 

[obi_waynne]

The engine takes much longer to warm up on idle. When you run a cold engine the emissions are particularly acidic and collect in the oil.

So when you just idle a car you're not really warming it up and you are building up the acids in the oil and it is likely to be building up carbon deposits much more quickly than it otherwise would.

Best way to warm up an engine is to drive it at the bottom third of it's rev range.

When an engine is already warm idling is not so much of a problem and you'll need to keep it running in traffic jams if you want the aircon to run without draining the battery.

Whilst stuck in snow I idled my engine for 4 hours and it was fine, although it had warmed up, that was a long story.

 

[Lunchmoney]

Right... I wasnt thinking of idle at start up. Just in general.

 

[TCJBOLDIE]

I would tend to think that sustained idling should not damage anything in a petrol engine HOWEVER I have been told that a diesel doing the same thing can cause glazing to the bores that needs a tear-down and re honing to rectify the problem.