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Warm the Engine First? Debunking More of Dad's Myths

13K views 63 replies 15 participants last post by  FixXxRR 
#1 · (Edited by Moderator)
Unheated oil? Clogging up pistons? Where do these things get started? Shutting down before hitting operating temp will have no short-term effect. As far as warming up an engine before driving away, that old nugget no longer applies, says senior auto editor Mike Allen.

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#46 ·
Are you 100% sure of that? And what if the temperature unexpectadly drops to the low end of what your oils rating is for??
Now you want to get into what-ifs? What if the temperature unexpectedly reaches 150 degrees while driving? If the temp drops lower then the oil is rated for, you will still face the same issues during the cold start regardless.

Anything longer than 5 7 min I agree. It depends on the outside temp and if you have a block heater. Why do you think almost ALL cars sold in Canada come standard equiped with a block heater??? Heats the coolant, which heats the block, which lets the oil warm up faster upon startup.
Now the introduction of a block heater? What next, the introduction of divine intervention? Yes, if you can use a block heater, that is excellent, but we are not talking about block heaters. If you have a block heater, that is great.

yes, the engine revs faster on high idle. But there is No load on the crankshaft; it's not moving the car yet. The load increases when you start to move the vehicle, right?
No load on the crankshaft from the rotating mass of the pistons, rods, etc? Whenever the engine is on, there is load placed on the crankshaft. The question then becomes, how much load is too much load? The load also increases when you increase the RPM's.

Yes, I know we are not taliking DumpaLube, but it was an example. It's the reason their engines stay running in the test. Not the oil additive. Because they drained all that additive away. Like I said, I was trying to use it as an example for engine longevity at low load. Even reving an engine with the clutch in, the bearing load is less than when your driving down the highway, agree?
Perhaps the load is less, but you are leaving the engine running longer with cold oil, which has a lower viscosity, possibly more oil shearing, and lower lubricating properties. Which is more damaging to the engine? The slightly higher load, or the extended idling with cold oil?
 
#47 ·
Now you want to get into what-ifs? What if the temperature unexpectedly reaches 150 degrees while driving? If the temp drops lower then the oil is rated for, you will still face the same issues during the cold start regardless.
I'm talking within reasonable limits of earth. You have to be open to all possibilities. All scenario's that could come up with cold starts.
Now the introduction of a block heater? What next, the introduction of divine intervention? Yes, if you can use a block heater, that is excellent, but we are not talking about block heaters. If you have a block heater, that is great.
The must put block heaters on for a reason, right? If they wanted you just to drive and go, then why waste the electricity plugging in overnihgt?

No load on the crankshaft from the rotating mass of the pistons, rods, etc? Whenever the engine is on, there is load placed on the crankshaft. The question then becomes, how much load is too much load? The load also increases when you increase the RPM's.
my bad, I should have said Lesser load, than when driving. I know there is a "load" on the bearings anytime it turns, be iot by combustion, or starter.
Perhaps the load is less, but you are leaving the engine running longer with cold oil, which has a lower viscosity, possibly more oil shearing, and lower lubricating properties. Which is more damaging to the engine? The slightly higher load, or the extended idling with cold oil?
I amy be wrong, but a higher viscosity is thicker. ie, 50W oil is thicker than 20W I know what you mean, but it's higher viscosity, isn't it???

Anyways, I have to start the mill up here, I'll be back to deliberate more tomorrow.
Night Dude
 
#48 · (Edited by Moderator)
I'm talking within reasonable limits of earth. You have to be open to all possibilities. All scenario's that could come up with cold starts.
This is called the introduction of a red herring and trying to add in unrelated variables to support your argument. You are attempting to bog the discussion down by introducing unrelated and silly scenarios. Who said we have to be open to all possibilities? Should we then also be open to the possibility that the driver forgot to put oil into their car? Or how about the possibility that snow storm freezes an cracks the hoses? Or, how about the possibility that the wrong viscosity oil was put into the oil container? Are we really talking about the chance occurances, or are we talking about reality? What if you wake tomorrow and it's 150 degrees out, are you going to warm up your car for 5 minutes? What if we go back into an ice age? Everyone knows we are talking normal conditions in terms of locality and oil selection.

The must put block heaters on for a reason, right? If they wanted you just to drive and go, then why waste the electricity plugging in overnihgt?
Yes, the block heater is to heat the block of the engine. You have once again introduced an unrelated topic, or red herring. Of course if the engine can be warmed before starting it, then its already warmed up. What is the purpose of the block heater? To heat the block. What is the purpose of driving right after starting? To heat the block. Do you not see the connection?

I amy be wrong, but a higher viscosity is thicker. ie, 50W oil is thicker than 20W I know what you mean, but it's higher viscosity, isn't it???
Anyways, I have to start the mill up here, I'll be back to deliberate more tomorrow.
Night Dude
Here is the definition I am using: Viscosity: The thickness or resistance to flow of a liquid. Viscosity generally decreases as temperature increases; application temperatures of urethane foam components are specified in part, to control viscosity at the dispensing gun.

Therefore, you are correct, it would have a higher viscosity when cold.
 
#49 ·
OK, we need to define some limits here. Because I think my idea of cold and your idea of cold may be totally different. I am not sure of where you live and what kind of temp extremes you get. Here, we get -35+ for 1-2 weeks at winter, adn a couple of weeks of +100F temps in the summer. I run 5W30 Royal Purple all year. I have honestly not seen a temp/viscosity chart for my car, so run the same all year long. Tonight, leaving work, it's about +12C 53 F. I fired the car up, and let idle for maybe 30 sec before I go. But if it was -12C 10F I would idle for maybe 60-90 sec. At -20C, I'll start her 15 min early to warm it up for ME, because I'm cranky after work and don't liek being cold LOL. But that's not the question here. Normally, at home, I would idle maybe 3-4 min then drive. At -20 or even -12C, I RARELY start and then go in the first 15-20 seconds. About the only time is when I have a fire Dept call, and someone else's life could be on the line so I fire and get going ASAP. IN the summer, I will satrt and go pretty much all the time, except in my Trans Am. She allways gets 30 sec min in the summer. But then, that's not an EFI'd everyday driver and totally out of this scope of discussion
 
#50 · (Edited by Moderator)
Regardless of how cold it is, the question remains, is it better to idle the car for an extended period with cold oil, or to drive the car in order to bring the car up to operating temperature faster. This question doesn't change due to the outside temp because either way you have to bring it up to operating temperature. And, according to the study I posted, and at the temperatures you are talking, it will have only marginally warmed up after only 5 minutes of idling, and therefore, you are still driving the vehicle with a very cold engine and have only increased the length of time it has run with cold engine oil.
 
#51 · (Edited by Moderator)
Ok seems we are not the only site on this subject........... here is somethings I found that apparently stands by what Bob is stressing, I do not know if it will be considered proof but apparently there is growing concern on engine warming with fuel prices and global warming. So this seems to be a growing topic and whether or not it all propaganda for global warming freaks or if due to global warming people investigated and found out the truth about drivetrane warm up is for you decide but apparently most links I read state that its best to warm up a modern car 30 seconds minimial and 1 minute maximum and then drive easily for the best way to warm up a car. Though I cannot find anything as of yet for older cars, it does seem that Bob's claims do infact hold ground with many who are on top of this subject.

http://forums.speedguide.net/showthread.php?t=126606

http://www.umaine.edu/hr/director/IdleFacts%202.pdf

http://www.bankrate.com/cnn/news/auto/2006...zing_car_a1.asp

http://www.jaylenosgarage.com/

http://forums.aaca.org/showflat.php?Number=425802
 
#57 · (Edited by Moderator)
I would just like to have someone explain to me why race teams warm up their engines before going into full out racing?
I see it quit often, the cars idling in the pits, and they say its to get the water and oil temps up, before driving off. Maybe the GM and Ford engineers should let them know that they are wasting their time


And this has NO basis on the topic at hand, so lets not go crazy with it, but today at work, I was thinking about this thread, and wondered why athletes stretch, and do warm-up excersizes before the big game?
Maybe they should just jump right in there and giver, hell!! without taking precautions, that will ensure their longevity in the game.
I know Bob, that was one heck of a red herringed- strawman, so I hope you can see this is all just in the name of good fun.

Oh, by the way, I'm still going to warm my engines up, by idling a few minute before I drive off, more so in the winter, than in the summer though.

Let the debate continue
 
#58 · (Edited by Moderator)
I would just like to have someone explain to me why race teams warm up their engines before going into full out racing?
I see it quit often, the cars idling in the pits, and they say its to get the water and oil temps up, before driving off. Maybe the GM and Ford engineers should let them know that they are wasting their time
Sometimes old habits are hard to break.

And this has NO basis on the topic at hand, so lets not go crazy with it, but today at work, I was thinking about this thread, and wondered why athletes stretch, and do warm-up excersizes before the big game?
Maybe they should just jump right in there and giver, hell!! without taking precautions, that will ensure their longevity in the game.
You cannot compare a human body to a motorized vehicle, they are vastly different. But, lets have some fun with this and make some comparisons. It is actually advisable to jog before stretching, which would be the same as driving a vehicle lightly to warm it up. This is why you will see athletes warming up by using calisthenics or some kind of light work out, and not just sitting there at idle. In addition, the body is able to adapt to the load placed upon it. In strength training, one of the adaptations is the increase in size of the muscle fibers of the muscles which have been subjected to overload. When was the last time you seen an engine adapt to the stress placed upon it by increasing its structure or alloy? I could go on, but we can see how silly such a comparison is.

And, nobody said to drive the car hard when cold.


I know Bob, that was one heck of a red herringed- strawman, so I hope you can see this is all just in the name of good fun.

Oh, by the way, I'm still going to warm my engines up, by idling a few minute before I drive off, more so in the winter, than in the summer though.

Let the debate continue
All in fun Leon.
 
#62 · (Edited by Moderator)
bike point of view.....

engine temperature and operating temperature:

the more high performance the engine is tuned, the more sensitive it is....
bikes are hypersensitive to this

there are several reasons why to warm....

ex: you must preheat the oven before you can bake the cookies...
ummm,,, ever hear... lick it before you stick it,, munch it before you punch it?
same applies.
its much more difficult to peal apart a cold grilled cheese sandwich.

for engines sitting for long periods of time, could/prolly be lubrication issues, thanks to gravity.
oil falls to the bottom.
if not mistaken, on the oil bottle, 10w40 means, when cold its not thicker than 40, when hot no thinner than 10.
engine, and oil designed around operating temperture.

again, all depends on design

generators designed to run at or around idle for hours at a time, most of its long life.

motorcross bikes, designed to run at wide open throttle for 20 mins at a time, short life

1. fuel mixture:
engine requires much more fuel to run when cold. i.e. choke/enrichment circuit
- starting the engine and turning it off, before operating temperature, causes rich condition making it very difficult on the spark plugs. the plugs will never reach a ''self cleaning'' state of operating temp to maintain life. repeated exposure resulting in premature plug failure
dont want to make it confusing, but a cold motor (specially carbed) is more prone to hesitate'' when you punch it, because its to lean while beyond/below operating temp range

2. cold seizure: piston to cylinder
the higher performance, the more sensitive.
engine designed around clearances and temp expansion.
ex. 2 stroke motors highly prone to cold seizure due to dramatic piston and cylinder expansion. the piston will heat and expand quicker than the cylinder, resulting in 4 point piston skirt contact to the cylinder. - not good- you may get away with this a few times, but then again, anyone can win the lottery. todays high performance 4stroke bikes, losely based on F1 technology (short skirt, light weight, quick rev) are very sensitive to this as well. resulting in severe cylinder damage and premature failure
piston/cylinder is the most typical damaged when cold, but not limited to, everything that turns has a designed operating temp.
your older motors, with worn clearances of course are not as sensitive, well to anything really...

basicly, metals change size with heat, so its best we give them time to change before we pin it.
those are the main issues that come to mind.
 
#63 ·
engine temperature and operating temperature:

the more high performance the engine is tuned, the more sensitive it is....
bikes are hypersensitive to this

there are several reasons why to warm....
IThe car warms up either way, the question is, is it better to have it warm up fast or to let it run longer while cold.

ex: you must preheat the oven before you can bake the cookies...
ummm,,, ever hear... lick it before you stick it,, munch it before you punch it?
same applies.
its much more difficult to peal apart a cold grilled cheese sandwich.
These are very poor examples to say the least. What do any of the above have in common with an internal combustion engine??

for engines sitting for long periods of time, could/prolly be lubrication issues, thanks to gravity.
oil falls to the bottom.
if not mistaken, on the oil bottle, 10w40 means, when cold its not thicker than 40, when hot no thinner than 10.
engine, and oil designed around operating temperture.
But, the oil pump pumps the oil to the top of the engine, and since it varies with engine speed, the higher the RPM the more oil which is pumped to the top of the engine.

again, all depends on design

generators designed to run at or around idle for hours at a time, most of its long life.

motorcross bikes, designed to run at wide open throttle for 20 mins at a time, short life

1. fuel mixture:
engine requires much more fuel to run when cold. i.e. choke/enrichment circuit
- starting the engine and turning it off, before operating temperature, causes rich condition making it very difficult on the spark plugs. the plugs will never reach a ''self cleaning'' state of operating temp to maintain life. repeated exposure resulting in premature plug failure
dont want to make it confusing, but a cold motor (specially carbed) is more prone to hesitate'' when you punch it, because its to lean while beyond/below operating temp range
The engine is going to be cold when you start it regardless, the question is, do you want the engine to warm up fast, or do you want it to warm up slow.

2. cold seizure: piston to cylinder
the higher performance, the more sensitive.
engine designed around clearances and temp expansion.
ex. 2 stroke motors highly prone to cold seizure due to dramatic piston and cylinder expansion. the piston will heat and expand quicker than the cylinder, resulting in 4 point piston skirt contact to the cylinder. - not good- you may get away with this a few times, but then again, anyone can win the lottery. todays high performance 4stroke bikes, losely based on F1 technology (short skirt, light weight, quick rev) are very sensitive to this as well. resulting in severe cylinder damage and premature failure
piston/cylinder is the most typical damaged when cold, but not limited to, everything that turns has a designed operating temp.
your older motors, with worn clearances of course are not as sensitive, well to anything really...

basicly, metals change size with heat, so its best we give them time to change before we pin it.
those are the main issues that come to mind.
Are we talking moto cross bikes or cars? In addition, nobody is advocating driving a car hard while the engine is cold.
 
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