Hey guys. I have a question, i didn't know where to put this so it is here now. please move if you think it goes elsewhere.

Every once in a while when i get home or my buddies house i let my car idle. I go inside for a little bit (5+ minutes) then come out and turn my car off. I do this with the thought that it might be a good idea to have some fresh oil flowing through the block, I don't think it would hurt. Then i figured instead of letting my ignorance possibly hurt my car i should ask the opinon of people who know something.

So have at it! Let the opinions and knowledge fly!

Thank you,
Rubix

P.*. hey billboost, i did read your post about testing the fuel pressure on my car in the O2 post a while back. I think i may take you up on that come spring time

Not mechanical related. Moving to General Chat...

In my opinion, it is always good to let the car cool down prior to shutting down. Especially in cold weather.

if anything its going to heat up more. IMO, not necessary at all.

that is more a thing for people with turbos, it allows the compressor to "spin down" aka cool off.

That'* what prolly stuck in my head. Before I was able to shut my truck down, I had to let it cool down for a minute or so to let the twin turbo'* cool off.

How is it that you think the oil in the crankcase, that has been flowing through your engine while you were driving it, is somehow any "fresher" when your car is idling? Elves do not show up while your car is idling and put fresh oil into your crankcase. This is the same oil that has been flowing throughout your engine picking up combustion contaminants, though your oil filter, into the crankcase, through the oil pump, and back through your engine.

In general, a car gets hotter when idling, because there is no airflow over the radiator to cool the coolant. This causes your electric radiator fans to kick in to provide airflow for cooling. This causes more electric load. All of this burns fuel at the rate of ZERO MILES PER GALLON, thus ruining your average gas mileage. While the engine wear for running an extra five minutes is probably negligible in the overall life of your engine, it is more revs, more friction, more heat; and *if anything* it just burns more fuel and causes more engine wear, waterpump bearing wear, belt wear, cylinder wear, and puts more wear and contaminants into your oil, thus shortening the oil'* useful service life, than if you had just turned your car off.

If there are any benefits to any components at all from idling your engine after driving, I am unaware of them.

In cold places people sometimes idle their car *before* driving it to get it warm so they will be more comfortable when driving. And in super cold weather this pre-warming often makes the car run better than if it were super-cold. But the same issues of more wear and zero MPG apply. But idling after driving? I can't see any point to it.

I have to agree with Bugsi. Letting your engine idle, especially when its not necessary is never a good idea. One, its an obvious waste of fuel and two, it simply allows for an accumulation of heat which only has the potential to damage or wear out componets. And I'm not sure what kind of neighborhood your leaving your car in, but leaving a car running and unattended is an invite for thievery.

Only in certain turbo applications as I said before, There are no bennifits that I have ever heard of for NA cars.

Letting any car warm up a bit before driving it will extend the life of your drive train. Why? Because the motor oil and transmission fluid have time to come up to pressure and to establish a flow to all the moving parts before you put the engine and trans under load. It is especially important that the engine not be revved up immediately after the engine starts and before oil pressure and flow have been established. This foolish practice results in spun rod bearings.

Most of us will not wait a minute before dropping into gear and pulling out, but it is really better for the car if we do. You can spend a little time after starting the engine to adjust the mirrors, the seat, the radio, your seatbelt, etc. before dropping into gear. When it is really cold, start the car before you sweep off the snow and scrape the windshield. Whether you wait a minute or not, drive the car gently for the first few minutes until it warms up, and the car will pay you back with less wear and longer life.

I gotta vote with the "no point in idle after" crowd. A couple of minutes before driving lets the fluids get up to pressure (or quite a few minutes if you're a freeze baby like me to warm the cabin).

But all after is gonna due, like stated previously, is heat up the engine bay until the fans kick in, and make any gearheads in the neighborhood wonder what'* wrong with you or your engine.

Also, keep in mind, if you don't have a remote start like some of us do, your keys are in there. It'* a ticketable offense most places, and an inventation for someone to decide they want your car more than you do. Even if locked, one broken window, and they have themselves a ride in under 30 seconds...