Why idle before shut off?

[Don87]

Thanks Spyderlk, exactally what I meant. gas being thinner than oil is going to seep past that top ring I believe and wash off any oil that was left below the ring, especially on an older engine. Also why do you not see more people pull into a parking space, hold the throttle to the floor and then turn their engine off, just wondering? LOL zman :confused2:

Actually if one thinks about it.............it may be worse on a newer engine.
On the old engines, gas was introduced through the intake manifold via the carb........newer engines introduce the fuel through an injector, which goes into the cylinder, via a spray nozzle.
Which could could cause cylinder wash quicker.............a dribble from the intake.......or a spray from an injector?

 

[SPYDERLK]

Several people have made comments about washing oil off of the cylinder walls by introducing fuel into the cylinders at shutdown....

[That would imply there is oil ABOVE the piston rings. If that is the case, how can cars go through thousands of start/stop cycles between oil changes, for well over a hundred thousand miles, and never use a drop of oil???

If the cylinder walls are getting coated with oil above the rings as many people say, why is none consumed??? ]

How thick a coating do you envision? How would you detect an oil level a drop low -- or even a couple hundred?
larry

 

[whodat526]

I
For our cars, most of us do not fly into a parking space at highway speed then kill the motor while it is still racing. We slow down, turn in, park, take it out of gear and turn it off. This has the effect of cooling it down.

Common sense will cool most engines enough for a shut down.

just do me one favor when u go to get out of your car after driving it for about thirty minutes and drive it normally before u pull in the parking lot look at the temp gauge when u put it in park look at the temp gauge and right before u shut it down look at the temp gauge i bet u dont see no change at all because there is not any

 

[whodat526]

Thanks Spyderlk, exactally what I meant. gas being thinner than oil is going to seep past that top ring I believe and wash off any oil that was left below the ring, especially on an older engine. Also why do you not see more people pull into a parking space, hold the throttle to the floor and then turn their engine off, just wondering? LOL zman :confused2:

if oil is on the cylinder walls above the piston rings u should overhaul that motor oil shouldn't be above the rings that is what the oil ring does clean the cylinder walls free of oil or it will some think of that please and the oil ring is the very bottom ring there will be three rings or more on each piston

and nobody pulls into a parking space and holds the throttle to the floor so u really think when u let of the throttle that cools the motor down right then and there wrong look and the temp gauge it doesn't move

think about what ur saying is u can boil water and then turn off the stove and that water will be cooler if thats the case make a vid of u boiling water and then cut it off and stick ur hand in it and lets see what happens
because this is all the same concept here

 

[Don87]

How thick a coating do you envision? How would you detect an oil level a drop low -- or even a couple hundred?
larry

That's the part that most people don't understand.

 

[Don87]

just do me one favor when u go to get out of your car after driving it for about thirty minutes and drive it normally before u pull in the parking lot look at the temp gauge when u put it in park look at the temp gauge and right before u shut it down look at the temp gauge i bet u dont see no change at all because there is not any

Do your check at 3 to 5 minutes.............not 30.
We will be waiting for your response!
Any engine...........I don't care who drives it, will heat up after shut down.
It doesn't matter how easy you drove it, whether it is air or liquid cooled........that's the nature of the beast.
There are ways to combat nature, but it will eventually overtake you.

 

[whodat526]

Like Roy Jackson said "At this point, I'd say the guys who shut down immediately will continue to do so..and the guys who idle for a few minutes will also continue to do so." and I tend to agree with him.

With sympathies to harpoonalt I do not think there will ever be an answer to this question. It is kinda like asking what the best color for a tractor is - too many opinions

everybody will do what they wont they have the right to sense they paided for it wether right or wrong

and the best color for a tractor is bright bright yellow lime green with hot pink racing stripes

 

[whodat526]

Do your check at 5 minutes.............not 30.
We will be waiting for your response!

well in five minutes the thermostat most likely wont even open it has got warmed up yet so nothing should be hot

 

[MossRoad]

if oil is on the cylinder walls above the piston rings u should overhaul that motor oil shouldn't be above the rings that is what the oil ring does clean the cylinder walls free of oil or it will some think of that please and the oil ring is the very bottom ring there will be three rings or more on each piston

and nobody pulls into a parking space and holds the throttle to the floor so u really think when u let of the throttle that cools the motor down right then and there wrong look and the temp gauge it doesn't move

think about what ur saying is u can boil water and then turn off the stove and that water will be cooler if thats the case make a vid of u boiling water and then cut it off and stick ur hand in it and lets see what happens
because this is all the same concept here

Some punctuation might help you make your points better.

 

[Don87]

well in five minutes the thermostat most likely wont even open it has got warmed up yet so nothing should be hot

We might be misunderstanding each other, or I read the original post wrong.........Run the vehicle for a while, park it, note the temp, shut it down..................turn the key on after 3 to 5 minutes..............note the temp..........there will be a significant increase in temperature.