Is idling bad for your engine?

[T1r9f85]

There are tons of articles online that say its bad for parts including spark plugs, cylinders and exhaust systems and tons of articles that say it's a myth!?? What do I believe???

[Yugguy1970]

My understanding is that a cold engine should not be left idling, best to drive off as soon as you can, get rhe engine warm.  This also helps blow out moisture from the exhaust that if left can become acidic because of the gases.

That said this is for normal engines that directly drive the wheels.

It's not as relevant for hybrids where the engine is designed to stop and start though I have noticed that even if not charging the Battery the engine will run to maintain temperature for efficiency I imagjne.

 

 

[Roy124]

Interesting question. 

You often see cars with steam from their exhaust when running from cold.  Does the hybrid exhibit the same or is its exhaust system drier after a run? 

[Cyker]

It's just because a cold engine wastes a shedload of fuel, and idling does not warm an engine up very quickly. It's best to just get ready to go (Kids all in and buckled up, gear in boot, let the cat out, glasses adjusted, seat cushion wiggled, gloves on, go back in to get forgotten thing #1, argue with the missus,  go back in to get forgotten thing #2, coat off then on then off again, take kids out to goto the toilet, put kids back in, coat back on then off again, go back in to get keys etc.), then fire up the engine and get moving, albeit not going too hard at it until it's fully warmed up!

As for exhaust steam, when my Mk4 is cold it does dump out a lot of steam on a cold day, but once it's warmed up it goes away so pretty similar to most petrol cars I guess! By comparison my old diesels produced a lot less 'steam' than my petrol cars did, but seemed to do it for longer.

 

[TonyHSD]

Excessive idling is bad for your engine particularly oil , oil consumption, oil degradation and cylinders wears off. Waiting a minute or two before you are driving off is also important for your engine health and should be done by all car owners. Steam from exhaust in cold engine, cold weather it’s a normal occurrence and also a sign of healthy engine and catalytic converter., more steam = cleaner burning. Spark plugs, catalytic converter and exhaust as overall not an issue as long as you start driving it especially if you do A roads and motorway speeds of 50mph and above these gets clean and nothing to worry about, however the oil is the most important thing to take care of, replace it sooner than usual if you do excessive idle your car. 👍

[Red_Corolla]

As long as it's up to temperature, I wouldn't worry about it. It used to foul the plugs on old carb engined vehicles but I don't think that's an issue on a modern fuel injection engine that's running much leaner. Cost and environmental impact are much bigger concerns. I don't see any good reason to do it, unless it's for A/C on a hot day or the vehicle has a freezer unit onboard.

The steam from the exhaust in cold weather is from condensate formed as the engine heats up. It's worse on cars used for short trips, because it accumulates in the exhaust silencers.