10 replies to this topic

[Shylos]

I remember there being a thread quite a while ago that talked about starting your Mini in the morning, and a few people said that it can do damage to the engine if you leave it idling to warm up before you drive, and that ideally you should get going asap. I was talking to the missus the other day about it but I couldn't remember what the reasons were people gave for this.

I've tried searching for everything I can think of but can't find the thread anywhere - does anyone know what it was called or have a link, and if not, at the risk of getting people to repeat themselves, can anyone give a reason as to why you shouldn't let the car idle for a few minutes before you drive off?

Thanks!

[Retro_10s]

Even Rover Printed in the owners handbook NOT to let the car Idle before setting off - much better to get in, start it up and drive it with the choke - let it warm up properly on the road

30 seconds is all that's needed to get the Oil Circulating (time taken to put your seat belt on check your mirrors) then off you go.

[Shylos]

Even Rover Printed in the owners handbook NOT to let the car Idle before setting off - much better to get in, start it up and drive it with the choke - let it warm up properly on the road

Why is this the case though - can the engine be damaged by leaving it idling, or is it just more efficient to warm it up whilst driving?

[miller 666]

i wouldnt mind finding this out either...

[Retro_10s]

Both

Much more efficient to drive the car than to let it Idle - Driving it warms it up quicker - meaning you can let the choke out sooner - so you use less fuel and cut down on carbon deposits inside the combustion chambers.

My British Leyland handbook states that letting the engine idle slowly when cold "leads to excessive Cylinder wear" and that "Far less damage is done by driving the car straight onto the road than by letting it Idle slowly in the garage"

[Shylos]

Thanks for that - would the same principle therefore apply to 'modern' engines, or are they generally far more capable of running colder, and warming up quicker?

[jjojjas]

Idling is a pretty ineficient way of getting the engine up to operating temperature, hence it stays "cold" for longer. If its cold, the oil isn't at optimum operating temperature so wear is exaccerbated.
Thats how it was explained to me years back.
Jas

[spiguy]

Even Rover Printed in the owners handbook NOT to let the car Idle before setting off - much better to get in, start it up and drive it with the choke - let it warm up properly on the road

Why is this the case though - can the engine be damaged by leaving it idling, or is it just more efficient to warm it up whilst driving?

I think this is one of those things that is more theory than reality. I've had many cars over the years, as has the missus and members of my family. All very different driving styles, and whereas me and my dad would tend not to leave the car to warm up at idle, most of the rest do this every winter for months. I suppose in theory you could have more wear as the engine will take longer to heat up. However despite all these different approaches, and the varying history of all the cars I've owned, I have never come across any cars which with basic maintenance, could not last for 100k or more.

Basically I think that extremes of car usage will 'wear out' an engine sufficiently more quickly so that you would notice - eg constant short trips, hard acceleration when cold on a regular basis, warming it up on idle ALOT, thrashing the nuts off it all the time, bad gearchanges etc.

However I don't believe that if you sit idling for a few minutes from cold every so often that it makes a blind bit of difference to your engine. Sure it will use up fuel (its not very efficient if the car isnt going anywhere - 0 mpg!) and its bad for the environment, but its not going to destroy your engine.

Change your oil when you should, don't hammer it from cold, dont thrash the nuts off it *all* the time, and then don't worry about it.

[jjojjas]

Change your oil when you should, don't hammer it from cold, dont thrash the nuts off it *all* the time, and then don't worry about it.

I'd take more notice of this than the idling time to be honest
Jas

[Shylos]

Thanks for all the replies and info - that's cleared that one up!

[liirge]

Even Rover Printed in the owners handbook NOT to let the car Idle before setting off - much better to get in, start it up and drive it with the choke - let it warm up properly on the road

Why is this the case though - can the engine be damaged by leaving it idling, or is it just more efficient to warm it up whilst driving?

and its bad for the environment..

Not necessarily True. Depends if you've fallen for all that rubbish.
I personally wouldn't let it idle, as people says the way to make an engine heat up is to make it do work, i.e move the car. You'll be fine as long as you don't take it from 900rpm to 8500 straight away!!!

Edited by liirge, 26 June 2009 - 10:55 AM.