Is it bad to leave a car idling?
Discussion
This had never crossed my mind before but after trying to wire in stereo accessories into my car today I just let the car idle just to ensure I didn't flatten the battery. My step dad then came out and said to.turn the engine off as it (his words) "causes a lot of wear"
Sounds like complete codswallop to me so long as you have sufficient oil and a good cooling system. So, does it do any harm?
Sounds like complete codswallop to me so long as you have sufficient oil and a good cooling system. So, does it do any harm?
Depends on the engine, cars would be fine I would have thought?
Bigger engines dont like it so much - tractors get very smokey if you leave them idiling all day, they're ment to be used up and down the rev range. Soon clears out once you do some proper work with them though.
Even bigger engines (ship engines) can nearly idle for days or weeks without a problem if they are just in dock and only providing a little generating power.
Bigger engines dont like it so much - tractors get very smokey if you leave them idiling all day, they're ment to be used up and down the rev range. Soon clears out once you do some proper work with them though.
Even bigger engines (ship engines) can nearly idle for days or weeks without a problem if they are just in dock and only providing a little generating power.
If the engine is cold, it'll take a long time to warm up. Since the ECU judges when to stop enriching for cold start on the coolant temperature, it'll take a long time before the enrichment stops. Excess fuel in the pistons can cause bore washing, which means fuel getting past the piston rings and into the oil, which is obviously a bad thing.
charltjr said:
Your step-dad is living in the past. It really isn't a problem, yes it causes wear in as much as the engine is running but it's not "worse" for the engine than normal running. Given you were leaving it idling for a sensible reason I can't see the problem.
This. Plus if you have a turbo its a good idea to leave it to idle for a bit on startup and shutdown.The manual for my 2000 Audi TT says "Do not warm up the engine when the vehicle is stationary. Drive off immediately" and the one for my '86 coupe said something similar, so it's not that outdated and as the TT has a turbo they don't seem to recommend it for that reason either.
I'd love to know why, though, I hate blind instructions like that. I was listening to someone explain it to his mate in the pub a few months ago, but they moved away before I heard the explanation so I couldn't earwig.
I'd love to know why, though, I hate blind instructions like that. I was listening to someone explain it to his mate in the pub a few months ago, but they moved away before I heard the explanation so I couldn't earwig.
droopsnoot said:
The manual for my 2000 Audi TT says "Do not warm up the engine when the vehicle is stationary. Drive off immediately" and the one for my '86 coupe said something similar, so it's not that outdated and as the TT has a turbo they don't seem to recommend it for that reason either.
I'd love to know why, though, I hate blind instructions like that. I was listening to someone explain it to his mate in the pub a few months ago, but they moved away before I heard the explanation so I couldn't earwig.
driving it away warms it up as fast as possible..a hot engine is a happy engine , warm oil , no cold enrichment blah blahI'd love to know why, though, I hate blind instructions like that. I was listening to someone explain it to his mate in the pub a few months ago, but they moved away before I heard the explanation so I couldn't earwig.
droopsnoot said:
The manual for my 2000 Audi TT says "Do not warm up the engine when the vehicle is stationary. Drive off immediately" and the one for my '86 coupe said something similar, so it's not that outdated and as the TT has a turbo they don't seem to recommend it for that reason either.
I'd love to know why, though, I hate blind instructions like that. I was listening to someone explain it to his mate in the pub a few months ago, but they moved away before I heard the explanation so I couldn't earwig.
Maybe something brought over when they translated the German manual. I don't think you are allowed to leave cars idling in Germany at crossings etc etc.I'd love to know why, though, I hate blind instructions like that. I was listening to someone explain it to his mate in the pub a few months ago, but they moved away before I heard the explanation so I couldn't earwig.
I often have my daily idling as its kind of my office. So if it's hot outside its running for the aircon and in the winter, for the heat. It's petrol and has 293,000 on the clock and still dosent burn any oil so it can't do much harm.
TallPaul said:
4key said:
This. Plus if you have a turbo its a good idea to leave it to idle for a bit on startup and shutdown.
Whys that then?For me, leaving an engine idling for a couple of minutes is preferential to switching it off and starting it again a couple of minutes later, but I avoid idling the engine from cold (as an idling engine heats up slower and gets lower oil pressure than a driven one). Leaving a hot engine idling occasionally for reasons like the one you mentioned seems fine to me.
I'm not completely sure, but this is how I see/learned it:
When the engine is warmed up (by driving the car) it's no problem to let it idle for a while.
It's not a good idea though to let it idle after a cold start. Most of the oil is down in the block, so lubrication isn't optimal. The oilpump doesn't do it's best job at idle rpm and the oil is warming up very slowly. All resulting in higher wear. Best case scenario is driving of after starting as stated in the users' manuals. You often see racing engines immediately make some (high) revs when started cold to get the oil around quickly.
When the engine is warmed up (by driving the car) it's no problem to let it idle for a while.
It's not a good idea though to let it idle after a cold start. Most of the oil is down in the block, so lubrication isn't optimal. The oilpump doesn't do it's best job at idle rpm and the oil is warming up very slowly. All resulting in higher wear. Best case scenario is driving of after starting as stated in the users' manuals. You often see racing engines immediately make some (high) revs when started cold to get the oil around quickly.
petrolsniffer said:
No.
Just look in places like siberia they leave cars running 24/7 if out in the cold as turning them off would result in the fuel lines freezing even refueling while running.
If you do want to turn the engine off for the night you have to find a heated lockup.
I was going to dismiss this as totally irrelevant until I clocked that the OP is in N.E Scotland Just look in places like siberia they leave cars running 24/7 if out in the cold as turning them off would result in the fuel lines freezing even refueling while running.
If you do want to turn the engine off for the night you have to find a heated lockup.
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