How is Idling bad to Oil?

[veryHeavy]

I'm curious about the mechanism of oil destruction. Also if a truck is left idling at a truck stop, how many "miles equivalent" would that be?

I'm thinking circa 1000 rpm would be 25 mph in top gear, so 10 hours idling == 250 miles of wear (approximately).

 

[LeakySeals]

My GF's dad lets his Sienna van idle for 30 minutes every morning. Drives me nutz.

 

[650NutKase]

Interesting info from Ford:

https://www.fleet.ford.com/truckbbas/non-html/DeiselTips/DLSIDLETIMESS.pdf

 

[bullwinkle]

Fuel dilution in a gas engine, & cylinder washdown/"wet stacking" in a diesel. If there is a load of some kind, a PTO or equivalent, it's not so bad-got to get everything up to operating temperatures.

 

[dwendt44]

Big rigs are often gauged with a 'hour meter' as well as an odometer.
History has shown that idling does no harm to those large diesel engines.
How this compares to our gasoline engines is anyone's guess.

 

[ShotGun429]

I bought a 2006 Crown vic ex police car last year, after finding out this car has a idle hours hour meter that only measures hours in park or neutral. Then after seeing it had over 6600 hours (+105,000 miles) i was concerned

but this car runs great burns no oil and i feel none if any damage has occurred,from so many idle hours.

 

[FCD]

Recently i watched a video from Regular Car Reviews of a review of a 2012 Chevy Caprice with an LS motor , it was a cop car, apparently the engine had over 2000 hours of just idling, apparently when the owner put a new more aggressive camshaft in it he found the original cam was very badly worn.
https://www.youtube.com/watch?v=LvynJKOdT4g he talks about it around the 3:00 minute mark.
An engine at idle operates in boundary lubrication, when driving at high speed on a highway an engine will be operating in a hydrodynamic regime, which equates to less wear ( in theory )

 

[lexus114]

Originally Posted By: dwendt44
Big rigs are often gauged with a 'hour meter' as well as an odometer.
History has shown that idling does no harm to those large diesel engines.
How this compares to our gasoline engines is anyone's guess.


when i drove otr, i idled up the motor for a/c or heat when i stopped for the night. was much better on fuel that way plus the oil pressure was better as well.

 

[SirTanon]

Idling tends to cause higher dilution from fuel seeping past the rings, etc.. Cars that experience lots of idle time and lots of short tripping tend to have used oil analysis with much higher fuel dilution% than cars that are driven a lot on the highway/longer trips.

 

[veryHeavy]

Originally Posted By: ShotGun429
Then after seeing it had over 6600 hours (+105,000 miles) i was concerned
6600 hours * 25 mph == 165,000 miles of idling wear (+105,000 actual). About 270,000 miles wear on your engine


Quote:
Interesting info from Ford:https://www.fleet.ford.com/truckbbas/non-html/DeiselTips/DLSIDLETIMESS.pdf
"One hour of idle time, is equal to approximately 25 miles of driving."

Hey that's what I said in my first post.
I made a good guess.

 

[buck91]

Our fleet has a LOT of E350/6.0L rigs and one thing our mechanics got very, very anal about was putting them into high idle (or shutting them down) when sitting post. Of course, the 6.0L is notorious for...well everything.

 

[bullwinkle]

Originally Posted By: buck91
Our fleet has a LOT of E350/6.0L rigs and one thing our mechanics got very, very anal about was putting them into high idle (or shutting them down) when sitting post. Of course, the 6.0L is notorious for...well everything.
That's a good move-we had a lot of issues with variable vane turbos getting stuck when OCIs were too long, or they were idled too much. Mine was fine, it went 250K+ on the original turbo-of course, it saw max boost pretty often...

 

[oil_film_movies]

Originally Posted By: FordCapriDriver
Recently i watched a video from Regular Car Reviews of a review of a 2012 Chevy Caprice with an LS motor , it was a cop car, apparently the engine had over 2000 hours of just idling, apparently when the owner put a new more aggressive camshaft in it he found the original cam was very badly worn.
https://www.youtube.com/watch?v=LvynJKOdT4g he talks about it around the 3:00 minute mark.
An engine at idle operates in boundary lubrication, when driving at high speed on a highway an engine will be operating in a hydrodynamic regime, which equates to less wear ( in theory )


Cool-ish video. Not really, but funny anyway....
That's it, its the high boundary metal-to-metal lubrication you get with low speeds that increases wear when idling.
The oil film collapses to zero in more of the engine when hydrodynamic is not fully supported, and metal contacts tribofilms (if ya got'em set up).

The Stribeck Curve (image google that surfing hydrodynamic relation if you dare to be geeky enough).

 

[The_German]

Rings "puff out" from pressure that gets behind them when under load. This causes an excellent seal.

An unloaded engine will coke up a bit more and more fuel will wash down the cylinder walls into the crankcase.

I don't think it's such a big deal really, just change your oil Severe Service if Idling can't be avoided or the Owner just loves to let his car run (bad for the environment and a waste of resources etc etc.)

 

[64bawagon]

We repurposed a Police pkg 2001 Tahoe with the 5.3, it had over 9000 hrs run time on it and around 100,000 miles. The thing ran like a champ, we did some fuel system cleaning, plugs and an oil change and drove it a few more years with nothing more than oil changes and a thermostat. I think most of the harm to gas engines was back before computer controlled FI, carbs weren't nearly as efficient at keeping the air/fuel mix proper.

 

[Panzerman]

My company truck idles a minimum of 4.0 hours a day sometimes alot more. I have never had a engine failure or used oil in several Ford F150s. The current truck as 219,000 and runs like a top so I really have to question the damage if any.

 

[OneEyeJack]

FI engines tolerate idling much better than a carbonated engine. An engine is a hot air pump designed to work and idling is a kludge to keep the engine running when not working. Temps and pressures are below optimum. Since there are no well designed and executed tests that I know of to answer this question I fall back on common sense and try to avoid idling if possible.

 

[daman]

Fuel dilution is the big thing, you need to change oil more often.

I've tore into engines(snow plow trucks) with excessive idle times and nothing outa the ordinary hit me in the face, piston skirts cyl walls looked like any other engine.

I have no issue with idling FI engines, just change oil more often.

 

[Gasbuggy]

Originally Posted By: LeakySeals
My GF's dad lets his Sienna van idle for 30 minutes every morning. Drives me nutz.


you live with them?

 

[virginoil]

Most OEM manuals state that excessive idling is an extreme operating condition and provides amended maintenance guidelines to follow.

What does your vehicles OEM manual say ?