Retardation or fact?

Discussion in 'SN95 4.6L Mustang Tech' started by Defleshed, Dec 4, 2003.

  1. I was casually chatting with a friend of mine and something in the topic led me to say "yeah in winter i usually start my car up, and let it idle for a good 5 - 10 min before i jump in and drive so it gets warmed up". my mechanic friend said "that'll really mess your car up, you shouldnt ever let it idle like that, not with a 4.6 at least". what the hell? this is contrary to everything ive heard, and to all logic that i've come to know. does there any bearing or truth to what he said?

  2. Sounds like retardation to me.

    However, there is no need to let your car idle for 5-10 minutes either, unless you just like it to be hot when you get in. With older, carbureted vehicles, you have to let them sit longer before you drive them. With the newer EFI cars, you don't really have to wait unless it just makes you feel better.
  3. :lol:

    your friend is completely WRONG! it is always a good idea to let any car warm up for a minute or two on its first start of the day. your mustangs cooling/oiling abilities are more than enough to keep it cool no matter how long it sits. i've sat in 100 degree weather with the a/c on for 25 minutes(traffic) without moving 1 foot and my car is flawless. ask your friend how come cops/taxi's(crown vic's) can sit with the car on for hours and not be affected. :nonono:
  4. I thought I read in the manual somewhere that if your car will be sitting at an idle for more than a couple of minutes, it's better to just turn it off. Maybe not in the manual, maybe here on stangnet. :shrug: Anyway, I know I read it somewhere, but like Premuim Speed pointed out, sometimes you sit in traffic for an extended period of time and your car still runs fine. I wonder what the deal is. :shrug:
  5. i read in the manual that there is no need to let the car idle after you have started it in cold weather-with that being said i usually wait a minute or 2.
  6. i can understand the guys logic, but even with the a/c on my car's fan only kicks on every now and then. with a crappy cooling system i can understand, but these 4.6l's have an outstanding cooling system. it is never good to let a car sit at idle IF it can be avoided, but sometimes you have to and 5-10 minutes is not going to cause any harm.
  7. As far as warming a car up, it will warm up faster by just driving it. Letting your car idle for awhile is not going to hurt anything. Like sitting in traffic.
  8. I always let my car warm up for a good 3 or 4 mins before hopping in again going. Winter or not, I just do it for some reason.
  9. i let mine sit running during the winter while i eat breakfast so it's nice and toasty when I get in.

    Like premium speed said though, if your friend were right, every taxi in new york would be in teh shop for repairs once a week :rolleyes:
  10. I always start mine a few minutes before i take off .. just depends how cold it is outside determines how long i let it idle. Noo more than 5 mins though. Just a waste of gas after that.
  11. From what I understand letting the EFI car idle is causing wear and tear on the engine. ALSO, 0 miles = 0MPG. So it could also be an environmental thing to "improve" gas mileage.
  12. your friend is wrong.

  13. just driving the car to the grocery store is wear and tear.
  14. The issue...and it applies to all engines, EFI or that most of your wear occurs in the first few minutes when the engine is cold and the parts have the most clearance (too loose). What you want to do is give it 30 seconds or so for the oil pressure to come up and everything to get circulating, and then start driving it - moderately. That way you bring the temp up much faster than you do with it sitting there idling (which, cold, is a very different thing from idling when at operating temp, and it can sit, in cold environments, for a long time without coming to operating temp - much more so than if you just start driving it), but you don't overload it. Then, when its up near operating temp, and all the clearances are much tighter and the wear will be less, you can start hitting it harder.

    An issue that makes the wear issue worse - especially in choked carburated engines - is that the mixture is richer at idle when cold, and all that extra fuel washes down the cylinder walls and removes your lubrication, as well as diluting your oil. But this is much more of an issue with carbed engines than with EFI.

    Taking it easy 'til its up to operating temp is a good idea. Letting it sit at idle, cold, and not warming up very fast, is a bad idea - and a waste of time and fuel. And letting it warm up in the winter for 5-20 minutes so you don't have to put your cushy ass on a cold seat has nothing to do what's good for the car.

    All the above is why your owners manual DOESN'T tell you to "warm it up" for 5, or 10, or 20 minutes before you take off. Most manuals say to let the oil pressure come up for a 20 or 30 seconds, and then drive easily the first few minutes.

    All that said, I know of LOTS of cars that get warmed up in cold climates for the comfort of the passengers, mostly without real serious wear issues (though most of them are not cars that are often driven hard) - though that's the worst environment to do it in. But if you're warming up your car several minutes for the BENEFIT of the car, and not your own comfort - you're wasting your time and gas, and actually doing what's NOT best for the engine.
  15. i really don't know which way to go on this one. i personally always let the temp needle go up quite a bit before driving, especially in the cold temps. i see what you are saying about everything being cold, and that is when the most damage is done. letting it idle it would stay cold longer. but if you are at a damaging temp like the first 20 seconds and are letting it warm up gradually at idle, isn't that better then driving and speeding up everything in the engine while at this damaging temp? i really think both ways is going to cause damage no matter what, and both ways are prob. so close in the damage they cause it really don't matter. i hope. i really don't know maybe ill cut down on the warming up time some. i really let it warm up good in the winter.

    what about storing the car over the winter, its just sitting and you have to start it up. i think it would be good to let it just idle up to operating temp. give it a couple of reves to help it get there.

    why is this pissing me off so much :bang:
  16. Kinda :OT: , but one morning my wifes running late for work. Jumps in and starts the car. then immediately takes off :eek: :eek: Plus she always brings the RPM's up to much when driving anyways :nonono:

    :fuss: I made sure she NEVER did that again.
  17. If I were the moderator I'd close this thread - and make it a sticky. Huck is DEAD on. The only that I'd add is that I'd bet that ALL recent owner's manuals INSTRUCT you to let your car idle for only 15 to 20 seconds then then DRIVE it.

    Thanks HUCK. You saved me the time to type it. :)
  18. i agree with you but i have never seen a case of a motor getting ruined while it was at idle with a proper cooling system. all the 1/4 mile WOT hits are FAR more dangerous than letting the car sit at idle. this point is.....pointless

    no(not enough to worry about) harm will be done by letting the car idle for a short period of time. cop cars have proven this for years. i know a cop who's car is continuosly running twice a day for up to 4 hours or more at a time. not a single problem. :nice:
  19. ding ding ding :D

    to put it bluntly....IT DOESN'T MATTER!
  20. You're doesn't matter a LOT. But my point, primarily, is that "warming up the engine" is of no benefit...and most experts (including the manufacturers) recommend NOT doing it. So why do it???

    And, regarding your point about idling and all the cop cars that sit around idling...they ALREADY AT OPERATING TEMP. We're talking about sitting, idling, unloaded, cold, where the wear is worst. And needlessly prolonging this wear.

    And this wear is worse in cold live in Texas...what do you know about cold??!! :D

    ding...ding...ding yourself. :D