Idling and engine oil

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Mar 25, 2008
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Kansas City Metro
I've always heard idling your engine for long amounts of time is hard on it but what exactly does it do? How does it cause moisture to find its way into the oil? I am speaking on liquid cooled engines, by the way.
 

KW

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Sep 4, 2003
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Central Arkansas
Sometimes they will not cool properly because the oil and coolant aren't circulating fast enough. Cop cars and delivery vehicles don't seem to have a problem with idling. On a local radio talk show that question came up when they had a guy in from a local shop. The caller asked about sitting in his truck with the air on to eat his lunch and cool off. The answer was that it would not hurt his pick-up as long as it was able to warm up / idle longer than 10 minutes. The guy said that he sat in his pick-up for 30 minutes everyday at lunch time. Look at some of the road department trucks. They sit and idle all day just for the guys to have a place to get out of the heat. I think a fast idle would be better than a tick over just to keep everything moving like it should.
 

dsmith41

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Mar 25, 2008
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Well shoot, diesel trucks can idle in a truck stop all night to keep the air/heat going in the cab and they still run forever. I was wondering if a gasoline engine is different, and if it is, then how? I have always heard idling is bad but I don't quite understand why. If the engine is up to temp and stays within the operating temp range, I don't see how it would hurt anything.
 
Joined
Oct 9, 2004
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New Braunfels
It can be hard on the engine because alot of the antiwear additives need to reach a certain temperature to work well. This is actually a sequance test (IVA) that is used by ILSAC to determine an oils capability to protect at cold idle. Now for the fun stuff. Once warmed up I have no problems idling my engine. WIth many electronics a hjeep for example cannot drive them effieciently at low idle .. THis is a nice device. http://www.4x4rockshop.com/scripts/prodView.asp?idProduct=13640
 
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Joined
Mar 16, 2009
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texas
It won't really. It'll kill your mileage of course, but that's about it. Fuel dilution will be up, but as soon as you start to drive around that should go away.
 
Joined
Apr 13, 2009
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Miami-Dade County
If idling was that bad over half of the cars on the road in Miami and Fort Lauderdale would be dropping like flies...Every where I go down here I see cars idling for very long periods of time with the a/c on...This goes on all year long...Im see them sitting there for hours at a time...Even in monster traffic jams no one shuts off their a/c down here.
 
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Oct 18, 2007
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CA
I really think the whole idle fuel dilution thing is carried over from the carbureted days. Why would a car like my TL which stays in closed loop from idle to WOT have fuel dilution issues?
 
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Jul 3, 2005
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NY
 Originally Posted By: BuickGN
I really think the whole idle fuel dilution thing is carried over from the carbureted days.
+1, I see Police cars sit in the same spot for hours waiting to trap speeding cars. In the winter the heat is on, in the summer the A/C, these cars are always up for the task when the time comes.
 
Joined
Mar 16, 2009
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texas
I have a carb, maybe that's why I think about fuel dilution. But on all the Blackstone uoa's that have higher fuel percentages they always say that it's probably caused by idling and stop and go driving. I wouldn't say a new car would have "issues" with fuel dilution, just that it's slightly higher when the rings aren't as firmly pushed against the cylinder walls when not under load.
 
Joined
Nov 26, 2008
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Arizona
 Originally Posted By: 72customdeluxe
Fuel gets past the rings and won't be boiled off because the oil doesn't get hot enough
s/doesn't get/may not get Both cars I've watched oil temps on will fully warm up just idling. However, both of these cars are equipped with coolant/oil heat exchangers.
 
Joined
Sep 28, 2002
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Pottstown, PA
If the car is warmed, I say little impact beyond throwing your odometer out of whack since you're getting zero mpg. It's different if you're idling it to warm it up ..and I'd say the effects aren't any worse, per se~, but you're, once again, getting zero mpg at a higher fuel rate.
 
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