Dave B

It seems that nearly every "non-car" person and even soon people in this forum think that the best way to warm up a car in the winter is to let it idle for 5-20 minutes. If these people only knew the damage they are doing to their motors. None seem to believe me when I tell them what happens by doing this poorly choosen warm up procedure. By letting a cold motor idle for a length of time, the oil does not circulate throughout the whole motor. Instead, it mostly "pools" around the lower half of the motor therefore increasing wear along cams and such. On a cold engine start up and under normal running temps, the ECU is running a very rich fuel program to make the engine warm up as fast possible. What does this mean for the motor? It means A LOT of fuel isn't getting burned and is seeping into the oil and degrading it quickly. Also, the rich exhaust will eventually foul the cat.

People just don't understand that you should start driving a cold car as soon as the oil pressure gets into the normal range which is about 30-60 seconds after start up. It sounds hard on a cold engine to begin driving nearly right away after starting it, but it isn't true. It is far less strenuous on the motor to warm up under load (ie driving). Why? Because the oil circulates better, the fuel program becomes leaner, and the increased tranny heat begins to help warm up the motor.

Why does this worry me? Because I will always buy used cars and you never know if the prior owner was misinformed about warming up a motor.


Dave

VQracer

ive been warming up my bike like that

1MAX2NV

iTrader: (5)

Yep, This is very true. The best way to warm up a car is as you described. Let it idle for about 30-60 second, then start driving. Another thing after you start driving is to go slow for awhile. I usually creep along my neighborhood around 15 mph until I get to the main road. I don't rev over 3K until the temp gauge is in the middle.

WoodEar

Cool!!! I never warm up my car, but I guess I was doing the right way the whole time then!!!

AntGVR4

i usually let it warm up for 2-3 mins at most
but i'll try what you say..
i never rev it b4 the temp gets to halfway like what 1MAX2NV said..

Ant

WoodEar

exactly my point!
never warm up, and it sees 7000rpm right away usually!

Jeff92se

iTrader: (82)

Ah, hate to be the doubting thomas here but, Dave, what do you mean by no oil in the upper end of the engine?? When the car is first started, it goes into the fast idle cold start mode, which as you say is also rich a/f ratio. But fast idle also means the oil pump is turning faster, which means it's pumping oil into the heads faster. I agree that driving the car slowly is okay and it will warm up the car faster. Just another reason to use synthetic oil. It pours much easier when cold, getting oil into the heads faster.

And Chris, 7000 rpm asap?? Remind me not to buy any of your cars in the future

WoodEar

Sure Jeff, don't ever buy used car from me
Btw, I have heard people laugh at new car buyers before, calling us fool for taking the biggest depreciation for nxt buyer.
but guess what? you never know if you are buying a beated up POS or not if you buy used.
You gain some, you lose some

PeelBoy

Heh. I agree. Specially when buying a sporty car.

There are times when buying a used car is best though.

As for warming up the car.. I usually let it idle for about 1 or 2 mins max and then drive it under 2,500 rpms until it starts to get warm and then I will drive it at higher rpm.

VQ: How do you like your R6? I was thinking about buying one, but I went ahead and ordered the new CBR 600 F4i last weekend instead. I can't wait to get it. It's such a sweet looking bike.

Dave B

Jeff-

You ask why does the oil "pool"? Because a 1100-1500 rpm warm up idle only is moving the oil pump at a 1500 rpm rate. Running the car at 2500-3000 rpms creates much better circulation.

Dave

Jeff92se

iTrader: (82)

Yeah all good points. I usually keep the revs down below 3000 rpm though.

And chris you said "beated" hehe! And I've had fairly good luck with used cars. That's what compression checks are for!

brianw

iTrader: (3)

Hmm. I normally do 0~60 second idle...

However on really frosty mornings I will let my car idle longer, mainly because I want to be able to see out of the windows.

PiotrC70

better after a 5 min warmup. It feels like it shifts smoother and all. Is it cause the tranny is warmed up also. Like most of you auto people, I hate that feeling in the morning, car is cold, you start driving and you feel your tranny shift from first to second bamn.... what do I have a torque converter...If you don't know what I mean.. it just shifts hard..

deathwish

Well, here's what I do...

First, you gotta put on some soothing music. None of that limp bizkit crap, maybe some sinatra or something from the big band era. Now, casually start to give her a little rub on the trunk. She's had a rough night, just loosen her up a little bit. Work your way around a bit, then slip off her car cover and get a little warm carnuba wax and start to massage it in. Pay special attention to her meaty areas, the fenders, A-pillars, etc. Light some scented candles. After a little of this, she'll be plenty warmed up and putty in your hands.

JimW

Oil pooling is not a major concern, as a matter of fact, just about every modern that I have ever worked on provides maximum oil pressure (and flow) at just over idle. Why? To prevent the unlikely situation that someone gets the revs up faster than the oil pump can provide oil pressure. No pressure/oil and high revs spells disaster. Warming up an engine excessively is not necessary, but it surely will not harm an engine in any way. So long as the engine gets up to operating temperature, then any of the "enriched" particulates will burn off, and there will be no increased wear or damage to the engine.
A idle warm isn't the fastest way to warm up an engine, but it surely isn't dangerous. That I can guarantee.

WoodEar

Yeah i realized afterwars it's beat beat beaten, but too lazy too edit.
hey, that's one good thing about being asian(non-abc) in us, you have to excuse my freaking spelling!

davis449

On any given cold morning I let my car idle anywhere from 60 seconds to 7 minutes it just depends on how warm I want the car on the interior. My car at startup idles at orund 1500 rpms so I think that's plenty to get the pressure up to par. I don't know **** about this kinda stuff anyway so maybe I should shut up.

DA-MAX

iTrader: (10)

when its REALLY cold!! cause you gotta let the ice on the windshield melt and everything and plus when the car has been sitting outside overnight in 30 degree weather I would think you'd need more than a minute to fully warm it up!! but I can see only 1-2 minutes in the spring and summer time!!

Johnny

only joking, but I don't warm up the car at all. What I do is try to avoid shifting over 2,000 rpm when cold. If I need to gun it to get out of the driveway and onto the boulevard, then I wait and it idles for a while there. Guess it's just habit. I heard warm-up is really to make the cabin comfy. But of course you don't want to rev the engine when it's totally cold either. Some do say driving gently is the best warm-up.

Dave B

Jim-

I gotta disagree with ya By idle warming an engine, it takes a long time to build up heat thru the motor. You end up getting hot spots in the motor therefore increasing the likely hood of a gasket failure. Your ECU also remains in the rich fuel program and contaminates the oil and cat. Most people don't drive long enough to burn off the fuel in the oil. Think about it for a second. You let your car warm up every morning and after 9 hours at work. That is a lot of gas going into the oil. Most people don't drive the 45 minutes needed to burn off the gas in the oil. I bet most people have a slow drive home and never get up to the rpms, compression, effienecy, or time needed to get a good burn off.

As for those of you who warm up your cars to get the ice off. I understand the problem, but don't you guys have ice scrapers? Also, running your defroster on the warm setting will never defrost the window as quickly as running the defrost on a cold setting. It will be a cold ride to work, but your windows defrost a lot quicker.

Dave

Jeff92se

iTrader: (82)

Wait, burn off the gas in the oil?? Once it's mixed in the oil(whatever miniscule amount that is) exactly how is it gonna burn off?? And there's that 45min thing again. There's no way an engine takes 45min to reach operating temperatures.

cheapo

Is this the same with motorcycles? My motorcycle instructor (at some motorcycle safety riding course) told me that you should warm up a motorcycle at idle, cause it keeps the engine from dying or stalling. Is this true?

PeelBoy

I let my bike warm up for atleast 2 mins or more.. I don't know if it's better for it or not, but I do know that I don't care for driving it while it's cold.

Synki

I let me car warm up for 30 secs and im off.

Dave B

Jeff-
You will burn off much of the gas in the oil IF you are driving at a nice constant speed for about 45 minutes on the average. I wasn't talking about a 45 warm up. I'm talking about a 45 minute burn off. Fuel is the single biggest factor in breaking oil down. That's why driving lots of highway miles results in very clean oil.

Cheapo-
I don't know what to tell you about a motorcycle. Here's my opinion. My buddies had sport bikes when I was in college and the bikes needed to be warmed up or else they rode like crap until the motor and carbs started to warm up. If you've got one of the newer bikes with a ECU and fuel injection, then there is no reason to let it idle warm up. The ECU should have a warm up program and the bike should ride pretty good. But damn, who would want to ride in weather below 60 degrees? It's down right frigid going 65mph on a 60 degree day.

Dave

Jeff92se

iTrader: (82)

How does it do that?? If the gas gets past the rings and mixes into the oil, how is the combustion process burn off just the gas and not the gas/oil mixture?? In that case it will burn off gas AND OIL. If you mean the extra fuel VAPOR that gets into the crankcase, then that's different and is part of the normal operating functions of the engine. And that certainly doesn't take 45min to get rid of imho. Be as detailed as possible becuase your not making any sense to me. And again if it takes 45 min to burn off this mystery gas you talking about then I would say 85% of the general public must have some screwed up oil becuase I would have to guess the ave one way time in a car is more like 15 min.

NYCe MaXiMa

iTrader: (9)

This is very interesting, I always hear that you should let your car warm up for 4+ minutes or you will **** it up. I usually warm it up for like 30 seconds or so in the summer time, but like 5+ minutes in the winter. Its like a general thing that all of the car public knows.

Question:
Can this have any kind of effect on fuel milage?

Funny, my neighbor is a manager at a Toyota/Lexus dealership and he always brings different demo cars, like Camry's Lexuses, Corolla's, 4Runners. and never once have I seen him let the car warm up for more then a minute.... guy just gets in, gets comfy and takes off. I am sitting there watching this like WTF? I thought he just doesn't give a **** about those cars, thats why he does that.... maybe he knows the truth?

Jeff92se

iTrader: (82)

Or maybe he dosn't give a **** because it's not his car!?!

Nismo87SE

I can offer some insight since my car came with a oil pressure gauge. Whenever I would start my car in the morning the oil psi would go to about 30psi. Once I start driving it hovers around 60-75psi depending on my rpm. I don't drive over 3000rpm until my oil reaches normal 11-14psi at idle. This is when our engines are at normal operating temp. BTW normally it would take my car about 6-7 miles before the oil reaching normal idle pressure. While it only took like 2-4 miles for my coolant to reach normal temp.

Mike S.

from someone who not only lives in a cold are but gets lots of snow....BUFFALO, NEW YORK!

On a cold snowy day....do you think people are gonna clear off their cars(up to 5 min) and THEN start up? NO....they start em up and then clear them off. Are they all doing damage? Well i guess so. If they are doing damage i don't think you'd see it in less than 200K. We ALL do this around here.....there are just as many high mile cars running around. I wouldn't sweat it. Plus I use Mobil 1

Mike S.

tomz17

I would tend to agree... "Warming up your car" for a longer length of time, seems to be common knowledge..

If everyone were so horribly wrong on this one, than a lot more cars would have serious engine problems...

Is there any possible way we could get a definitive answer on this??>.. does the Nissan manual say how we should warm up the car??


--> Btw.. There's this one guy on my street, that gets into his car every morning, starts it up, and floors it in park.. (he holds throttle fully open for like a min or two), and then goes)... I was about to tell him what a moron he is, but he drives an old POS anyway, and I don't particularly like him!! <--

MaxPerformanceSE

iTrader: (2)

I had a friend in high school who claimed to be a "car enthusiast". He warms up his 91 Accord just like the guy on your street. I was in his car once and he started up his car and revved it to 4.5 rpm and kept it there until the needle moved to the middle position. Black smoke came out of the exhaust. That's ok because he's a "car enthusiast".

JimW

With all the detergents and other additives in everyday oil, your oil will not get saturated enough with fuel to make a difference. The few times when you do get the oil up to high temperature is enough to burn off any fuel dilution. I've taken apart many engines, (in my past life I was a Chrysler "B" technician) Idle warming a vehicle is not bad for it. You will not incur any damages to the engine. No such thing as hot spots either. You will not damage any gaskets by doing that. Please tell me where you got that information from. I idle warmed my Maxima (at least my mother did) every day for 6 years and 95k, and never did I incur any problems. I idle warmed my old CFI 5.0 (85) for 3 years. I idle warmed my old 83 Dodge Van for 17 years and 104k, I idle warmed my 79 Chrylser Lebaron for 3 years, ditto with my 82 Civic.
Also, just an FYI. The VQ motor has that "reverse flow" cooling system (I think that's what Nissan called it) For that, and a couple of other reasons I forgot, the VQ motor heats up very fast. Faster than most other modern V6's that I know of. (Even my 2.7T takes about 2 minutes longer than my Max did)
Driving a cold engine will heat it up quicker, but no matter what you say, idle warming will NOT HURT the engine. Most modern owners manuals will tellyou that it's not necessary, and that it wastes gas, but it DOES NOT hurt the engine.
I do have an Ice scraper, but unless you've lived through a NorthEast winter, you'll never be able to understand how long it can take to chisel through an icy coating of winter "stuff"

got rice?

iTrader: (2)

The problem on really cold mornings is t hat once the ice is off, it'll start fogging up and icing again unless the windows/windshield is hot enough to keep that from happening. During the summer/spring/fall I idle for 30 seconds and I'm off (put on seat belt, adjust radio, leave), but during the winter I let it idle while I scrape off the snow/ice/crap... this can take 4-10 minutes. I know it's not the best thing for the car but it's not as bad as you make it out to be.

Dave B

Here ya go guys, this is one of my sources. These are some excerpts taken from R. Sikorsky's book "Drive it Forever" (1993). Chapter- The Cold Start

..."no more than 15 seconds of engine idling should be required."

..."do not try to warm the engine with prolonged idling. Years ago this was the accepted practice, but with today's engines and increased knowledge of the mechanics of engine wear and fuel economy, most engineers are in agreement that prolonged idling of a cold engine will only do harm."

..."cold idling engines won't warm as fast, lubricate as efficently, or burn gasoline as completely as one that is in gear and moving.."

..."a cursory check of a number of new car owner's manuals will show that most manufacturers are in agreement with the above.."

..."on a very cold day, a car may never reach total efficiency, as parts such as transmission, wheel bearings, axles, and tires never have a chance to become fully warm."

..."much of the enriched fuel mixture is never burned and some finds it way into the oil, where it has a diluting effect and upsets of the protective qualities of the lubricant."

..."forget what your dad and grandad told you about warming up an engine-you are dealing with a new breed of engine, fuels, and oils."


As you can see, I not making this up and has been re-written in numerous other publishing. Mr. Sikorsky goes into much stronger detail about the above statements with graphs, fuel ratios, oil standards extra, and examples of failures related to poor cold start procedure. I'm not saying you're gonna blow up your motor by prolonged engine idling, but I am almost certain you are adding life to your motor by driving it as soon as possible. I think the auto professionals probably have a lot more data and experience than most of us do iin this forum. More often than not, they are right.


Dave

JimW

If you change your oil every 3k, you won't suffer any detrimental effects due to fuel dilution.
I would like to see some of the failures of these engines that were subjected to his ideas of poor warmup operation. As I said before, I've got a rather extensive automotive background as well, not an engineer, but I was ASE certified. I personally have NEVER seen a failure that can be attributed to improper warmup.
In ideal situations, lengthy warmup is not necessary. In many climates it is a necessity. When the mercury drops to a couple degress above freezing, and the temp in my garage is still in the mid 20's, there's not way that I'll start up my turbocharged car, buckle up and drive off, even at low speeds. I will allow my car to idle while I lock my house, lock my garage and take a look see around the car (for low tire pressure and/or leaks) and then get back behind the wheel. Total idle time is still close to 2 minutes. I must be certain that all is well before I pull off. That the oil has reached the turbos, and then I will proceed with very low boost until the oil temp is up to operation temp. Which in cold weather can take up to 10 minutes of regular driving.
Coming from a person who frequents the WOT position as often as I do, I'm rather surprised that you believe this book. You will shorten your engine's life more with frequent WOT operation than you will by warming up at idle speeds.

Dave B

Jim-

You're comparing your twin turbo 2.7 to the VQ. Sorry buddy, these are two different animals. A turbo needs to idled longer to get full circulation thru the most expensive part of the motor-the two turbos plus you should idle it down after hard driving to prevent "coking" of the turbos.

Believe what you want, but Sikorsky is also ASE certified, a mechanic, has numerous other automotive credientials, and is highly respected in his profession. Out of curosity, if you were ASE-certified, then why didn't you do all your tranny work and install of all you mods on the Max? Rebuilding a tranny and installing a torque converter isn't a rocket science. I don't know where you get your info other than just from "experience". You haven't been apart of engine wear analysis nor have you researched the information with engineers from auto makers, oil companies, and gas companies. Like I said, believe what you want. But more often than not, most techs and engineers will tell you what Sikorsky tells you.

I do "work" out my motor a bit, but not near as often as many do in this forum. I might run it up to 5000-6000 in 2nd and some of 3rd 5 times a week, but I don't speed shift the car. I think operating a motor in it's normal operating range of idle to 6500 rpms isn't gonna do significant damage to the motor as long as the engine and tranny are warmed up. As many know, the cold start is the hardest operation on your engine. Anyways, operating an engine in it's normal operating range allows the motor to be broken in fully. By operating a motor from idle to 4000rpms nearly all of it's life and has redline of 6500 rpms will mostly result in a quick failure of the gaskets if you start running it above 4000. WHy? Because the gaskets are not used to increased pressure of operating the motor at such high rpms therefore they fail and leak (or blow). I think you do more damage to your transmission by shifting it hard at a high rpm when racing then you do damage to the motor revving it high (not exceeding redline).


Dave

Jeff92se

iTrader: (82)

I'm still waiting to hear how the fuel gets burned off when it's "mixed" in with the oil(however small amount that is anyway) IMHO you just give the source w/o explaining why. That seems like blind faith to me. So he's ASE certified, ASE certification didn't stop the Nissan mechanic from screwing up my motor and the ASE certificate certainly didn't stop the Nissan dealer from not honoring their own repair warranty. Point being I don't hold the certification in high regards by itself. Jim's experience holds more weight than the certificate does.

JimW

I was in fact ASE certified, just didn't renew it when they expired. I didn't do my own tranny work because I was no longer a technician, and since I only have a one-car garage with a one car driveway, I didn't have the space to park the car for a couple of weeks while I rebuilt a tranny. It's almost impossible to rebuild a tranny when you only have 1-2 hrs a day to work on it. You're right, it's not rocket science. (I have a 9-5 now, or should I say a 8:30-6:30) Also keep in mind, I do have a degree in Automotive Technology, as I was on my way to becoming an automotive engineer. I had a 3.5 GPA, in classes like Alternate Powerplants, Advanced Thermodynamics, Advanced Metallurgy, Fundamentals of innternal combustion engines, Physics I, II, and Advanced Physics. Hydraulics, Engine analysis (where we dismantled non-working engines and had to rebuild them to run on an engine dyno)
Then of course, there's the other stuff :blueprinting, welding, engine and chassis lab, refrigeration, etc. I've got a pretty extensive background in the study and repair of autos, for someone of my age.
As far as "experience", I was changing oil at 12, pulled the top end off my first engine at the same age. Worked for a small repair place in Brooklyn from 15-18. I had enough experience to know how to wire spark plug wires for any domestic engine with all the existing ones removed. I'm the same person who could tell you the model and engine size of a car just by hearing it start up.
As far as the other mods. I installed the ones that I wanted, and paid for the others. The Y-pipe I wouldn't attempt because of the lack of air tools and time. I went to an exhaust shop that I know the owner of, and we installed it together.
I still haven't heard any technician (that I know of, or that I worked with) say that idling an engine up to operating temperature will harm that engine, neither did I see you post specifically what type of damage that it can cause. Gaskets? I don't think so. The job of a gasket is to provide a liquid and or gas barrier between the junction of two metal (or other material) joints.
Not trying to discredit you or anyone else. I just have to question the validity of what Sikorsky wrote.
Now, as far as the VQ and my 2.7T motors are concerned, although they may be different, they are still similar. With the exception of the Turbos, I still have a 2.7L aluminum block engine that is spinning those turbos. If that's the case, by allowing the turbos to be fed with oil sufficiently before driving off, I'm killing the long block. Either way I lose. That's why I have trouble believing what Sikorsky says.
So here's my breakdown:
first mentioned was oil pressure. I countered that most engines make full oil pressure just over idle speed (which is true) In most cases (say 75%) the oil pump is pumping full supply and pressure at a measly 11-1300 rpm.

Then the oil "pooling" was mentioned. I responded that pooling shouldn't occur, as full pressure is reached just over idle.

Then you mentioned "fuel dilution of the oil, and running rich" I can agree with fuel dilution of the oil, but in the modern era of ECU's and OBD, the car isn't running very rich, only in the startup phase. Once running, the ECU will try to lean it out asap, to clean up the exhaust emissions. That's another reason for the pre-cats. Placing the pre cats close to the exhaust ports of the cylinders makes sure that they "light-off" quickly, very soon after the engine starts. Now, to make what I said as clear as mud. Changing the oil at 3,000 miles will make sure that there is no damage to your engine due to motor oil breakdown, or acidic content. (I don't believe that Nissan calls for 3k oil changes in it's light duty cycle, I believe the sever duty cycle calls for 3k oil changes. Severe duty meaning door-to door service, operation in extreme temps or in dusty enviromnents)

I still don't agree. Idling an engine before driving it up to full temperature is NOT going to damage it.

TBag

Sounds like a DuraLube infomercial... I've been doing this for almost 6 years on my 95 Max with 167,761 miles and I've never had a gasket failure or engine problems. (knock on wood) Damn, I guess no one wants to buy my car now... and I have to confess..I live in Va and it was damn cold this morning and ice and snow were on thick... I let my car idle for 20 minutes!!! doh! But my *** was nice and toasty though And she shifted real smoothe also...
Their! I confess! Please dont think any different about me! I thought I was doing her a favor!! But after all thes years I've just been abusing her...