Patman
Staff member
I never let my vehicles idle to warm up and never have needed an engine rebuild either. Think of how much $$$ I've saved since I started driving in 1986!
Idle time?
- Thread starter Chris B.
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With modern EFI engines, I think this "fuel dilution" thing is being overstated. OK, the fuel mixture is richened up when the engine is cold, but it not like the old manual or automatic choke days, when there was no precise control of the mixture.
That said, my car, like my girlfriend, go a lot better when they are warmed up.
Dave
That said, my car, like my girlfriend, go a lot better when they are warmed up.
Dave
I guess I have the best of a bad situation:
I keep my truck inside an unheated but insulated garage. Depending on ambient temps, I plug in the block heater for 30-60 mins. I use a winter front in temps colder than -15 C. I let it idle for 2-3 minutes, just long enough to lock the house and close the garage door.
I live at the end of 8km gravel road, very twisty with a posted 50 km/h speed limit. I have very few neighbors, so I can drive gently to the highway without worrying about getting rear-ended.
Once at the highway, the motor is already at operating temp, even at -40, the axles have also been fully lubricated and warm, and the transmission is good to go. I hoof it to quickly reach highway speeds.
Then you have those idgits who live along the highway. On a cold -40 morning they pull out and drive at 50-60 km/h to baby the motor while causing a traffic jam of pulp trucks, transport trucks, and impatient commuters behind them.
Of course, they're far too simple to pull off to the side and let traffic by. So you have to follow them for 10-20 km while they gently warm up their putt-putt.
I keep hoping a pulp truck rams those idiots off the road.
So use common sense. If you immediately have to get up to highway and especially freeway speeds, better warm the motor up first. If not, 2-3 minutes should do it.
If you're worried about "fuel dilution" then move to a desert environment with minimum temps of +20 C and max temps of +45 C.
Jerry
I keep my truck inside an unheated but insulated garage. Depending on ambient temps, I plug in the block heater for 30-60 mins. I use a winter front in temps colder than -15 C. I let it idle for 2-3 minutes, just long enough to lock the house and close the garage door.
I live at the end of 8km gravel road, very twisty with a posted 50 km/h speed limit. I have very few neighbors, so I can drive gently to the highway without worrying about getting rear-ended.
Once at the highway, the motor is already at operating temp, even at -40, the axles have also been fully lubricated and warm, and the transmission is good to go. I hoof it to quickly reach highway speeds.
Then you have those idgits who live along the highway. On a cold -40 morning they pull out and drive at 50-60 km/h to baby the motor while causing a traffic jam of pulp trucks, transport trucks, and impatient commuters behind them.
Of course, they're far too simple to pull off to the side and let traffic by. So you have to follow them for 10-20 km while they gently warm up their putt-putt.
I keep hoping a pulp truck rams those idiots off the road.
So use common sense. If you immediately have to get up to highway and especially freeway speeds, better warm the motor up first. If not, 2-3 minutes should do it.
If you're worried about "fuel dilution" then move to a desert environment with minimum temps of +20 C and max temps of +45 C.
Jerry
heyjay:
If I were a driver like you described who lives on the highway, I'd just start the car, ease her onto the highway and cruise at the speed limit.
Someone correct me if I'm wrong, but highway speeds are fine (even cold) as long as you use light throttle to get there and don't let the engine get above 3,000 RPM. In my 4-speed automatic car, I can go 82 MPH before I'd get above 3,000 RPM.
If I were a driver like you described who lives on the highway, I'd just start the car, ease her onto the highway and cruise at the speed limit.
Someone correct me if I'm wrong, but highway speeds are fine (even cold) as long as you use light throttle to get there and don't let the engine get above 3,000 RPM. In my 4-speed automatic car, I can go 82 MPH before I'd get above 3,000 RPM.
That sounds a bit extreme. Engine temps should get up top the level where oil is flowing nicely and clearances have gotten to something like 1/2 way to design clearances. Maybe 100F engine temp before gentle freeway driving.
Engine load is as important as RPM and your automatic that is keeping engine speed down is loading the engine harder than opne that lets it turn a bit faster. That's one of the reasons some automatics lock out the top gear until the car gets to some operating temperature.
Hmmm. In real life, I actually just kind of drive 65 once I get on the highway. 80 MPH would be bad for my license.
And actually, the 80 MPH at 3,000 RPM is 3rd gear in my car. 3,000 RPM in 4th would be 120.
My car *is* somewhat overpowered, so I'm thinking 65 MPH isn't excessive shortly after startup. I did some math one day, and reached the conclusion that 50% throttle in my car was 92 MPH.
Here was the math:
1996 Chevy Caprice Classic at 4611 Lbs
%HP HP used MPH
10 26 20
20 52 33
30 78 60
40 104 75
50 130 92
60 156 107
70 182 115
80 208 120
90 234 126
100 260 133
And actually, the 80 MPH at 3,000 RPM is 3rd gear in my car. 3,000 RPM in 4th would be 120.
My car *is* somewhat overpowered, so I'm thinking 65 MPH isn't excessive shortly after startup. I did some math one day, and reached the conclusion that 50% throttle in my car was 92 MPH.
Here was the math:
1996 Chevy Caprice Classic at 4611 Lbs
%HP HP used MPH
10 26 20
20 52 33
30 78 60
40 104 75
50 130 92
60 156 107
70 182 115
80 208 120
90 234 126
100 260 133
Long idling increases the likelihood of water condensate on the cylinder walls and into the oil, fuel fouling of the oil, etc. I know a tribologist who insists that the acidification that follows from the weak sulfuric acids formed by combustion and fuel sulfur causes more warm than the old model that "oil is down in the sump and the engine is dry up top". If you use an ester, there will always be some oil on the metal parts, even after extended shut down. And the sacrificial AW compounds do their job at startup.
Plus, many people warm up the engine then race off - what about the tranny, gear, and even the bearing greases? I have always driven off once oil pressure stabilizes (to guard against a filter blow out) and then gently letting the car warm up IN TOTAL - **** , I do not turn on the heater until the car is warm! Flesh can heal - engine wear is forever.
Plus, many people warm up the engine then race off - what about the tranny, gear, and even the bearing greases? I have always driven off once oil pressure stabilizes (to guard against a filter blow out) and then gently letting the car warm up IN TOTAL - **** , I do not turn on the heater until the car is warm! Flesh can heal - engine wear is forever.
Yes exactly. Many automatic transmissions appear to "lug" the motor down a bit. That would create FAR more load on the motor than a lower gear and higher RPM.
The 4L60E in my 2000 GMC Sierra is programmed to shift FAR differently cold than hot. When cold, especially in temps below -25 C, it will hold gear to 2,500 RPM, and OD will NOT engage.
The owner's manual mentions this and explains the primary reason is to speed warm-up.
So when I drive at 50 km/h from my house to the highway, my motor is running at 2,000 - 2,500 RPM.
So there goes the theory that a motor at 1,200 RPM warms up faster than a motor at 2,500 RPM.
Jerry
Warm ups are for old, carburated, medium or heavy trucks. Only a fool tried to drive off in one of them with a cold engine. Modern engines will run cold as long as only moderate demands are made of them. The ubiquitous automatics will ease any stumbles. Warm ups may do as much harm to the engine as good. Warm ups definitely waste gas and harm the environment. Bottom line, you may as well drive off.
The main thing we're talking about is wear. Sure a modern engine will run just as well cold as it does warm, however, the wear is greatly increased.
$1 a day??quote:
Originally posted by Gary Allan:
Pocketbook? This is where most of you miss the recommendation. Add up all the fuel ...and the fuel dilution from idling a car (getting ZERO mpg) and even if you attribute ONLY $1 a day (indexed for fuel costs and added oil changes) ..over the average 10 years of ownership ..you've spent more than a non-rebuild (do you know of more than a few engines that have been rebuilt in 10 years of ownership?) ...which you won't need if you just warm it for the factory recommended 30 sec. and drive conservatively for a few miles.
All of you would be better served, IF you really want to spend that same money, by installing a block heater.
That is, it has been determined that any minor wear attributed to running a cold engine that has reached stable lubrication (30 seconds in all owners manuals that I've read) is less expensive in terms of long term costs/benefits to warming an engine before running it.
Now you people of the -40 Minn locations....
..you have my sympathies
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Don't just count the fuel cost. Then again ..most of you spend more belonging to the 3m/3k oil change crowd to worry about added maintenance costs. There's also added fuel fouling of the plugs as minimal as that may be ..but if you're in the 3/3 club ..you're probably in the 12 - 15k plug club as well. Keep in mind that you're getting ZERO mpg while idling.
Are you so sure? If I change oil every 500 miles (and for the moment throw out any rhetorical disclaimers to neutalize my arguement) I would probably never have to rebuild the engine for the entire time that I own it ...or even my son owning it....but you would have spent MORE than a rebuild in doing such "high maintenance" on it.
Now "detune' that high maintenance ...and cross over to "long warm ups". Your intent is to make the engine experience less wear ...yet you will be spending MORE money than you will experience in wear over your ownership (unless you start very young ...and know that you're going to grow very old with the same car).
Again, how many of you here have actually rebuilt ANY engine that wasn't flogged for street racing or some special abuse mod use? I'll venture that virtually none of you have. Many of you have bought used cars ..with many many miles on them ..have you had to rebuild the engines? Did the PO warm the engine for 5 min every cold morning? What most of you want ..or are trying to achieve ..is to have a "like new" engine ...even if it costs you more than it will be worth (cost vs. benefit) in lost service.
The preponderance of evidence suggests that extended warm up beyond the 30-60 second range just doesn't pay (deep sub zero drivers are somewhat exempt).
Car ownership doesn't require a career in over maintenance to get the best cost/benefit from it.
Hey ...it's just my opinion ...it's like a sphincter ...everybody has one
Too long...
Like others have stated, the difference will be minimal, but in terms of "optimal" protection, idling for approx. 30 seconds is desirable in regards to establishing a hydrodynamic lubricating film, which is the most favorable form of lubrication, in comparison to taking off immediately and relying upon boundary and mixed-film lubrication to get the job done.
ZMoZ
We should ride the bus? Why should one not be concerned about MPG gasoline is very exspensive. I wish i had money to burn like you but most of dont.
We should ride the bus? Why should one not be concerned about MPG gasoline is very exspensive. I wish i had money to burn like you but most of dont.
I 100% agree.
For optimal wear, idling 30 seconds is ideal, but the vehicle is bought to serve your needs, and I'll take higher wear in return for my own personal safety and comfort
I really wonder about this whole idle idea. I really want my truck to last forever and will do anything to help it get there. My Dad is old school and he lets his car idle for 10-15 minutes on cold days, sometimes longer!!!! He has always got 200,000+ on a lot of his cars through out his life so long idle can not be that bad. I do tell him that is WAY WAY to long but he still likes to do it and still gets high mielage from his rides!
My neighbor is also like this he lets his truck idle for long periods of time on cold days and his 1990 Silverado has over 200,000 miles on it.
My neighbor is also like this he lets his truck idle for long periods of time on cold days and his 1990 Silverado has over 200,000 miles on it.
Patman
Staff member
It was over 35F here this morning and I still saw my neighbors cars idling in their driveways. That's what makes me angry.
There is simply no need for it at all when it's not even cold out.
There is simply no need for it at all when it's not even cold out.
Start the engine and drive away SLOWLY. Idling from cold the fuel doesn't atomise and raw fuel washes the cylinders. Not inducive to good wear characteristics.
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