I got a big debate question with my cousin here.

he keeps on telling me there is no need to warm up the car in the morning
even its -7 outside early in the morning when I head off for school.
I got the old traditional pass down knowledge from the experts that we should always give the car a few minutes warm up in winter days.

what exactly is the term "warm up", is it necessary or what??
or maybe I am doing it wrong for the last 4 years....

what are you guys' comments.
what disadvantages if you don't warm up ?

 

With your Fit you can start it a drive off, however, at sub-zero temps I would recommend a minute or two at idle to assure that the oil is finding its way around and then drive 'conservatively' till the cold engine light goes off.

If you quickly take it to a high rev/engine load you run the risk of reduced lubrication and cylinder/bearing wear.

In other times a warm-up meant starting the car and switching on the heat and going back inside till the interior was warm. That practice is not recommended.

 

Agreement with KC here. I personally crank the car over, then fiddle around putting on my seatbelt, adjusting the radio, etc. In the 30 seconds or so it takes me to get settled and ready to drive, the engine has had a chance to get oil up pumped into the valve train and splashed up into the cylinder bores. Then I drive like my grandmother till the "cold" light goes out.

Modern engines are much better at running "cold" than those which were carbureted - carbs do poorly at getting fuel atomized, and often those engines lacked power until temps rose to where the fuel evaporated and blended with the air stream.

I had a 64 which, when cold, collected liquid fuel in a small puddle directly below the carb, inside the manifold. Once heat levels rose, there was a phenomenon where the fuel puddle suddenly evaporated, and things went from running lean to very rich to normal all in about 1 second. If I happened to be on the throttle too much at that second, I would get a nice backfire.

 

I feel that cars nowadays don't need as much warmup as older cars. But like the others said, drive gently until the temp gets to normal.

 

What affect does revving the engine higher have if it's not warm yet? The oil's circulating in a couple of seconds.

 

Here's some car myths that a grip of people believe. Some will even dismiss this and become defensive about their beliefs: Consumer Reports Cars Blog: Car care: Myths vs. reality

Warming up your car by driving it is better. This way you can warm up your transmission fluid, your brakes, your catalytic converter, and your engine all at the same time. If you let it sit and warm up, you end up with a warm engine and a cold everything else, and you will need to drive it easy for the same amount of time to warm everything else up anyway. Might as well do it all at once and not waste gas while polluting the atmosphere in idle.

 

the cold oil is thick and viscous, it won't lubricate the engine components as well as when it's at operating temp.

 

Okay, but at higher revs it warms up faster. Is that a wash?

 

For the majority of cars most of what CR has to say in that link is true.. as long as the driver understands that he still needs to give it a minute to get the oil pressure up where it needs to be after initial start and then he drives its gingerly.

We also have mechanical oil pumps.. so if you let it idle for 30-45 seconds after start up, and then you hold the revs for a couple seconds between 1500-2000rpm you will raise pressure and increase flow to splash and coat parts that may not have gotten it yet, and most likely have not entered full form lubrication. This goes a LONG way to fighting wear and tear.

One thing to keep in mind is that even though the coolant light has gone off.. the engine is not warmed up. The oil can take between 15-30 minutes to get up above 150*F where the protective 20w part of the 0w20 is starting to come into effect.

There are some cars where you want to let the coolant get up to temp before you start driving. In an AT you have the advantage of the hydraulic pump circulating the fluid and that friction heats it up for you!

In an M/T it can take an even longer period to get the gear oil up to temp. Most Hondas use the gear lube equivalent of a 30w engine oil. So where the engine oil has the advantage of all that combustion heat to warm it up, the trans has to rely on radiated and conducted heat from the engine as well as internal friction to get the fluid up to temp.

 

I just start it up and gently drive away.