[ninesixtwo]

Originally Posted by Tom K.

As some of us age, coy may be the best we can aim for!

Tom

[techlogik]

VW has always said just start the car and go...warming up is a waste.

[Castel]

Originally Posted by BRAISKI

With my old car RSX-S, I never warmed it up and I just drove off, of course I do not drive it aggressively right away. For 7 yrs I had the car I never had any problems with the engine whatsoever. I used regular oil and change the oil with the intervals they suggested about 25k, sometimes I do it around 23k.

This might be an Apple vs Oranges comparison but just want to put some perspective.

Wow... 25000 km with regular oil, that's like 15k miles. In Canada's cold weather! I wouldn't want to buy your car.

[IN54NITY]

Originally Posted by TrackRat

What I posted is correct.

With advanced engine cooling designs the water pump(s) can be cycled as needed. That means you can use the maximum coolant temp generated in the cyl. head to almost immediately provide heat to the interior of the car instead of heating the block faster at the expense of interior heat.

Oil heats much slower due to lower thermal conductivity. Water heats ~ 4x faster than engine oil. An aluminum oil pan with lots of oil in it will heat up even slower with the vehicle in motion as the cold air will draw the heat out of the oil via the aluminum pan. Works good in the Summer however.

http://www.engineeringtoolbox.com/th...ds-d_1260.html

What? Water has the highest specific heat capacity of just about any substance/liquid known to man, thus it heats much slower than oil. That why it's used to cool cars, nuclear power plants, etc.

Here's a link from engineering toolbox even:
http://www.engineeringtoolbox.com/sp...ids-d_151.html

[Castel]

Originally Posted by Bamaben

I think all would agree that you want your oil to reach optimum temperature as fast as it can. The only way to do this is start the car , maybe wait 5-10 seconds , then start driving, but keep it < 3k rpms until oil temp is right. it isn't how fast you go, it is all about the rpms you're turning that matters, so don't worry about going 70, just put it in 6th.

starting the car and letting it sit there is horrible for the car simply because you have cold thick oil not lubricating sufficiently for a long period of time.

I mean..don't we all agree that starting the car is what puts more wear on the internals than anything else? then why would we want to start it and let it run cold for 5 minutes ?

just start the car and start driving it carefully.. thats it

Good grief!!

You want the oil to get warm as fast as possible but that doesn't mean you should go out right away and push it WOT which will in fact warm it up the fastest.

The reason why some want to wait a minute or two is to let the oil warm up a little before putting any load on the engine, basically running it at the slowest speed possible until the oil is flowing at least (i.e. idle).

Either way I don't think there's a big difference in waiting 1-2 mins and driving off slow vs. driving off slow right away. I feel more comfortable with the 1st option, seems like the oil is flowing and the car is ready. 3k RPM isn't nothing, that's 3k times each cylinder going up and down.

[comebackidlci]

Originally Posted by nuM nuMs

Does no one read the manuals to their cars?! On page 57 of the 3 series manual its specifically tells you to NOT wait for the engine to warm up while stationary and to start driving right away at moderate speeds.

+1

I hate when people think they know more then the people who MADE the car

[325high]

Originally Posted by comebackidlci

+1

I hate when people think they know more then the people who MADE the car

that's not the point. the title of the thread is 'scientific evidence on engine wear'. just b/c BMW says it doesn't mean crap to me (and BMW isn't even making any claims; they're just saying don't wait for warm up). i wanted evidence; not a BMW engineer's opinion. And if evidence doesn't exist (which it seems it doesn't), a BMW engineer's opinion on the interaction between cold oil and a motor is barely more valuable to me than any experienced mechanical engineer's opinion. I'm sure this forum has plenty of engineers so the opinions on the forum are interesting to me; far more interesting than the recommendations from the manual.

[dtc100]

Originally Posted by auger330

that's not the point. the title of the thread is 'scientific evidence on engine wear'. just b/c BMW says it doesn't mean crap to me (and BMW isn't even making any claims; they're just saying don't wait for warm up). i wanted evidence; not a BMW engineer's opinion. And if evidence doesn't exist (which it seems it doesn't), a BMW engineer's opinion on the interaction between cold oil and a motor is barely more valuable to me than any experienced mechanical engineer's opinion. I'm sure this forum has plenty of engineers so the opinions on the forum are interesting to me; far more interesting than the recommendations from the manual.

If you admit evidence does not exists, then the logical thing to do is to listen to the BMW engineers, until such time you find evidence to the contrary.

[Castel]

^^^ C'ommon... How can he know if there is or not any evidence for this? That's why he made the post in the first place, to ask. He is saying that opinions on the issue are interesting as well. Asking about the effects of cold oil on the engine and how it affects it during idle as opposed to moderate engine speeds has not much to do with some douche replying RTFM...

[ninesixtwo]

Originally Posted by Castel

I don't think there's a big difference in waiting 1-2 mins and driving off slow vs. driving off slow right away. I feel more comfortable with the 1st option

why bother? just don't. it's in your head. as you duly noted.

[dtc100]

Originally Posted by Castel

^^^ C'ommon... How can he know if there is or not any evidence for this? That's why he made the post in the first place, to ask. He is saying that opinions on the issue are interesting as well. Asking about the effects of cold oil on the engine and how it affects it during idle as opposed to moderate engine speeds has not much to do with some douche replying RTFM...

He was trying to find evidence to support his own belief, at least I suspect that is what he is doing.

The vast majority of drivers do not idle to warm up before driving, therefore we know the manufactures must design their engines to meet such driving habit. If you believe idle is better, go for it, just don't try to dismiss those who do not idle, especially when the car manufacture says don't idle.

[fdriller9]

I'm not sure if this was mentioned and I'm not reading the 3 pages....

When you let you car sit and idle to warm up, you don't warm up your transmission. I usually wait for a minute before driving off....gently of course.

[John 070]

I had always heard that the only reason to warm up a vehicle is for comfort, i.e. the driver wants the interior warmed up before he drives. That's about it. Otherwise, as everyone else has said, drive gently at first.

[John 070]

Originally Posted by bbbradley

Do you have a source for that number?

Regardless of the impact, there is an impact, and if you can reduce it and eliminate something that has no benefit, what is the harm?

Start the car, drive gently for a couple miles and off you go.

Agreed. That number, well, it's fictitious, of course.

http://www.dec.ny.gov/docs/air_pdf/diesel.pdf

[Quasimodem]

It is very important to not redline your engine before it is warm. But I don't see anything wrong with driving it gently to warm it up.

If you dont think warming up an engine is important, all you have to do is think about one reason as to why US Carriers were superior to Japanese carriers in WW2. This is because US carriers were designed with hangars below the the flight deck which could open to the air outside. Why was this important you ask.... Because this allowed the mechanics to warm up the aircraft engines while they were arming and preping them, before they were spotted on deck. In contrast, Japanese carriers had mostly enclosed hangars with little ventilation, so to avoid killing all the mechanics loading munitions and stuff, they couldn't warm the planes up below decks. For the Japanese, once the planes were spotted, they could start warming them up. This added step caused a delay in attacks being launched from Japanese carriers putting them at greater hazard of being attacked in a vulnerable situation.

Why did navies consider it important to warm up the aircraft engines? Because to win a carrier battle, both the Japanese or US navies needed as many planes arriving on target as they could get. And that means they had to get them off the deck and into the air with good engines. To get into the air from a carrier meant that the pilots needed to redline the aircraft because of the short distance available to generate lift under their stubby wings. Japanese and US forces knew from experience that there were greatly increased failure rates (engines exploding) if the planes redlined their engines without warming up their engines.

There, my 2 cents.

[comebackidlci]

http://finance.yahoo.com/insurance/a...s-and-Mistakes

#2

[Bamaben]

Originally Posted by Castel

You want the oil to get warm as fast as possible but that doesn't mean you should go out right away and push it WOT which will in fact warm it up the fastest.

The reason why some want to wait a minute or two is to let the oil warm up a little before putting any load on the engine, basically running it at the slowest speed possible until the oil is flowing at least (i.e. idle).

Either way I don't think there's a big difference in waiting 1-2 mins and driving off slow vs. driving off slow right away. I feel more comfortable with the 1st option, seems like the oil is flowing and the car is ready. 3k RPM isn't nothing, that's 3k times each cylinder going up and down.

I didn't say to go WOT as soon as you crank it.
And idle is 800 times a minute the pistons go up and down so 3k rpms is only around 2.2k more than idle which isn't much.

[dtc100]

Also for some of us waiting for the engine to reach "operating temperature" before WOT means no chance to WOT. I don't think there is evidence WOT your car before reaching operating temp will harm the engine. Five minutes of initial gentle driving is what I do before I rev hard. No idle for me.

[335beeeemer]

Let it warm up a few minutes get the fluids moving. It would be a good idea in general to lubricate the hpfp and other parts of the engine before driving too.

[F32Fleet]

Originally Posted by auger330

I spent some time on past threads and on google and i haven't found anything beyond forum conjecture regarding whether or not warming your car up in the winter is bad for the engine. Anyone ever come across a reputable source's opinion? It'd be nice to see something from Popular Mechanics or something.

Why doesn't Mythbusters work on things like this? instead they seem to make up myths just so they can bust them!

Idling has a couple of problems:

#1 Usually the driver just takes off like he would on a summer day, but doesn't realize that the transmission has not yet warmed up. This can actually do more harm to your transmission.

#2 Your valvetrain is still covered with oil upon start up, and it takes less than a minute to get it moving to the far reaches of your engine. We use synthetic afterall.

#3 Modern engines with their aluminum alloy blocks are designed to reach operating temps very quickly in order to meet emissions goals.

#4 Idling causes the vehicle to run rich longer and you don't get optimum ring sealing; both of which increase fuel dilution.

[bbbradley]

Originally Posted by *********

I'm not sure if this was mentioned and I'm not reading the 3 pages....

When you let you car sit and idle to warm up, you don't warm up your transmission. I usually wait for a minute before driving off....gently of course.

This bears repeating. A warm engine from the wasted fuel and excess emissions while simply idling but a stone cold gearbox, differential, and other driveline components.

[vasillalov]

When going for a cold start, my rule of thumb has always been (summer or winter):

* Start car
* Wait till rpms settle down. This usually takes around 20 seconds in the summer and up to 1 minute in -15F winters. In the mean time, carefully pump the clutch and the brakes couple of times to get the hydraulics moving.
* Drive off carefully, keeping the rpms under 2500 and wait till engine reaches normal temps. I even try to avoid using the heater so that the engine can warm up quicker.