Originally Posted by
trism
ive posted thisd a few times
warming a car up is the worse thing you can do, for a few reasons, if you have a search youll find them all, but here is a quick run down
1. idling causes fuel wash. the excess fuel in the cylinder not being burnt literally washes the oil off the cylinder walls, removing lubrication
2. emissions control devices, specifically the catalytic convertor work when heated up. idling the car isnt going to heat it up, so for the 5 minutes its warming up all the toxic nastys are spewing out the exhaust.
3. youre wasting fuel warming up. the ecu automatically supplies more fuel when cold to prevent stalling. thus wasting petrol (and causing fuel wash)
4. you sit there for 5 mins warming the engine up thinking youre sweet, then pull out and give it a hit thinking its all fine. well its not. where does the power go through before it hits the wheels? the gearbox/rest of the drivetrain. you hit it, and your 'box is cold still and you cause wear on the drivetrain.
thats a basic run down on why its not necessary. simply get in, start the car up and drive away, taking it easy until the temp reaches operating temperature, that way everything warms up at the same time and you dont damage anything