When i first start my car, the engine is completely cold. I usually keep it on before moving the car till it reaches the first quarter after the '40' mark. Is this a good practice? How long do you guys keep the engine running before moving if the outside temp is around under 20 degrees?

This would really help me.

///S320

 

I don't warm it up at all. I do tend to drive more gently until it's warm and I can tell the transmission shifts a little differently when cold. I don't think I'm hurting anything by just firing it up and driving off, but I'd be interested in someone with more technical knowledge's opinion.

Z

 

I dont warm either - like zin, I drive slowly and do not stress the engine until its warm. In the handbook for this 2003 E I have and the 1993 I used to have - It said the same (Not to warm your car while standing still) The guys at the SL55 forum confirmed the same ..

 

From what I know, you don't have to warm up a fuel injected car. However, I would keep a light foot until your oil warms up so that you don't prematurely wear out your engine. Cold oil does not lubricate as well as when it is warm.

 

Letting a car idle to warm up is not good as it wears more than if you were driving just a little be easier than normal.

 

As with any first start of the day, it is best that the oil flow has commenced before moving the machine. Simply put, that means, the oil pressure should be "normal" during idle. Usually this does not take more than 10-15 seconds. After that, you are ready to go. Idling a machine until it warm up is a waste of fuel, and unnecessary wear. However, it may cause mildly accelerated wear, because the oil remains cold for a longer time, its viscosity is too high (thick) and its lubricity is reduced.

The MB S-class has a program that takes the ambient temperature and the engine temperature into account when shifting gears. There is a misconception that you should not rev higher, in lower gears during this period. But the Mercedes stays in a lower gear for a longer time, because the "load" on the engine becomes less, although, if you accerate hard the revs will be too high. Maximum wear occurs at high loads when the engine is cold, such as a condition created when the gears shift up too soon. The wear is not necessarily frictional wear alone since the oil is not warm. It is mainly components that are stressed in tension and compression at a temperature that may be below the glass transition temperature, causing premature breakage of piston rings, rods, etc. Also, the fuel does not burn completely as well with a cold engine, causing higher emissions and clogging of the catalytic systems. In short, when the engine revs higher in lower gears, it reaches operating temperature even quickly, thereby reducing wear, and providing maximum power and fuel efficiency.

The standard procedure should be accelerate smoothly, and get going ASA oil pressure is normal.

Zindallas, you were correct, but I thought I'd provide the reasoning behind your technique. I hope that helps, ///S320

Y. Chachad

 

Has anyone used the Kenlowe Hot Start kit?
www.kenlowe.com/pre-heaters/cars/index.html

 

Thanks Ychachad and others for sharing your information.