What is worse for the engine - idle vs. cold start

[SteveD2]

Apologize for cutting in with a quick question.

I've always wondering about "idling is bad" deal. I have read it in my owner manual, car books, etc. about this.

But, the thing is in a typical winter morning, say around 20 degrees F (no snow or ice, just plain cold), my car takes about 10 solid minutes to warm up to operating temperature (middle point in temperature gauge). About 3-5 minutes just to reach the lower temperature mark of the operating range.

If I idle for about 10 minutes, the car seems to run better the rest of the day.

Throughout the day, I never let my car idle though.

So what should I do? Hope somebody can explain a little bit more? Thanks!

 

[jsharp]

quote:

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Originally posted by Larry Oo:
Apologize for cutting in with a quick question.

I've always wondering about "idling is bad" deal. I have read it in my owner manual, car books, etc. about this.

But, the thing is in a typical winter morning, say around 20 degrees F (no snow or ice, just plain cold), my car takes about 10 solid minutes to warm up to operating temperature (middle point in temperature gauge). About 3-5 minutes just to reach the lower temperature mark of the operating range.

If I idle for about 10 minutes, the car seems to run better the rest of the day.

Throughout the day, I never let my car idle though.

So what should I do? Hope somebody can explain a little bit more? Thanks!

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My opinion is that idle isn't harmful. If you have adequate oil presssure, cooling, and mixture control I don't see how it does any harm...

 

[DEWFPO]

Most municipalities don't keep their emergency vehicles for very many years, unlike most of us. The many use hour meters to maintain therir vehicles and ignore the mileage.

As well, I've never experienced one race up even after sifting for ridulous numbers of hours idling with all the lights on. They do however, ususally have two big alternators that can put out city light amperage at idle, and the ECU's compensate the idle speed for the load.

DEWFPO
DEWFPO

 

[moontan]

prolonged idling is also hard on the cat con

 

[WeyounDS9]

Lets not forget the hotsoak on the injectors when you shut off.

 

[KW]

I guess it would depend on how cold the motor was and if the ilde speed was to low. My Jeep idles at 800 and drives down the road at 1200, so I'd quess it could idle til it ran out of gas without hurting anything.

 

[Rand]

I just got a remote start.. I'm not lazy or anything but at -10(F) I like to start it up so it idles for 2-5min before I go out. I dont see this as harmful? Oh and my ranger idles at about 1000rpm(cold). It also has a feature you can let it idle with key out and if the brake is pressed it shuts off.. handy for those Dairymart run-ins and whatnot.(to shift out of park you have to press the brake)

Rand

 

[Road Rage]

Some tribologists believe that the idling increases the amount of water condensate on the cylinder walls, which can react with sulfur in the fuel to form weak acids, that can be harmful over time. It also would use more of thre ani-sludge additives to counteract. And that assumes an engine in good condition, with no blowby. I say once oil pressure has been reached (10-20 seconds), the best thing to do is to drive off and drive moderately.

 

[White 03]

I have never heard of this before. What happens to the injectors?

How are injectors normally cooled?

Thanks

quote:

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Originally posted by palmerwmd:
Lets not forget the hotsoak on the injectors when you shut off.

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[heyjay]

quote:

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Originally posted by White 03:
I have never heard of this before. What happens to the injectors?

How are injectors normally cooled?

Thanks

quote:

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Originally posted by palmerwmd:
Lets not forget the hotsoak on the injectors when you shut off.

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A "hotsoak" used to be a big problem for older fuel injectors. The motor is at operating temp, say hot stop-n-go in city driving with the A/C at Max.

You stop and go shopping or to a restaurant for 2-3 hours. The residue of fuel on the injector tip turns to carbon, leaving deposits behind.

This cycle repeats over months and years, and deposits keep building up until they coat the plunger in the injector.

The plunger now begins to stick, so the solenoid in the injector can't fully close the injector when you shut off the motor.

This will cause some odd symptoms: the gasoline will dribble out, flooding the cylinders and causing a prolonged/rough hot start; the fuel rail will depressurize, so unless you wait for the fuel pump to build pressure, you will have to crank a lot when cold; the deposits cause a very poor fuel spray pattern, so again you will have to crank a lot when cold; and, you will get fuel in your oil.

Supposedly, fuel injectors made within the last 10 years are very resistent to this problem. A good fuel injector cleaning (MotorVac or a good additive) will cure/prevent this problem.

Jerry

 

[Palut]

Chevron gasoline has Techron in it, which they claim cleans fuel injectors. Does the amount of Techron in the gas do enough to prevent that buildup?

 

[moribundman]

The Techron injector cleaner fouled my plugs once. I'd say Techron is pretty strong stuff. How much of it is in the gas, I don't know.

 

[heyjay]

quote:

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Originally posted by Palut:
Chevron gasoline has Techron in it, which they claim cleans fuel injectors. Does the amount of Techron in the gas do enough to prevent that buildup?

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I suppose if used from new.

Constant Interstate driving and a car may never have deposit problems. 100% city driving and you may have to use additional additive, with caution of course.

Jerry

 

[Road Rage]

quote:

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Originally posted by moribundman:
The Techron injector cleaner fouled my plugs once. I'd say Techron is pretty strong stuff. How much of it is in the gas, I don't know.

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Here is an analysis I wrote on the topic:
http://forums.s2ki.com/forums/showt...ghlight=whats+in+those+fuel+injector+cleaners