question for you guy's
 

Very simple question actually. Is it a good idea to warm up your car in the morning before you start driving? I know on some cars you do and on some you are not suppose to.

Can't speak to S class specifically, but I like to start er up, give it a minute or two before I head out on my way, no matter what I'm driving.

SFBIGBODY,

No technical info for S-Class either and here is my experience.

I start to drive as soon as the idle speed drop which means the computer is happy about the running condition. It takes around 15 seconds in summer or 40 seconds in winter. Plus my daughter prevent me to idle too long since she had a lesson about protecting earth O3 layer.

After start I didn't use full speed (let's say under 60km/h) until coolant reach working temperature to prevent any potential damage to the engine.

But I do suggest fully warm up if you live near the highway. I believe driving on highway speed when car is cold will hurt the engine.

Thanks.

Howard

My commute is only 2 miles/3 minutes so I'd spend more time warming it up than actually driving to/from work. I do try to avoid hammering it when the engine's cold but usually forget.

Howard said it - soon as the R's drop down from coldstart, engage gear and set off.

Don't rev > 4k, don't produce boost, don't load it.

I live 2mi from the highway, start it up, revs settle, and I'm off and up to temp about 2mi upon entering the interstate.

Letting it sit used to be more an issue before EFI and you'd foul up the plugs / cylinders / etc due to cold start running rich. Nowadays it's more your oil isn't getting up to temp in time to best circulate, and also it causes the oil to "milk up" (curdle) as it's not boiling off the moisture.

Used to have to abide by such regimented litany in the 930... never boost a cold engine / never shut off an engine w/o boosting WOT (that last bit is actually in the owner's manual - keeps the wastegate from seizing). Becomes ingrained routine 8-)...

Yes, As Paul remind me.

I seldom wait to warm the car but I do wait before shut it off if drove it hard. Since both of my cars are Turbo charged.

I pay especially attention when fueling during highway stop.
It's so easy pulling off the highway, entering the gas station then shutdown and fueling. This will kill the turbo as it doesn't got enough cooling. Hence the hot Trubo burn the oil and be cloged.
So I idle at least one mins before stop and fueling after highway driving. This will keep the oil and coolant circulating and cool the turbo down.

Thanks.

Howard

I don't even like starting my cars and shutting them immediately off - if they're started they get warmed up and run. Get good @ rolling them around the driveway / garage 8-).

Good point on shutdown Howard, standard practice fersure. Tho the oil coking is less an issue in today's watercooled units, with afterrun pumps and what not - but still I do it.

STILL WISH someone would share the Star fan-temp secret handshake that allows it to kick on 10* sooner! W211 guys get all the fun 8-/

Typical me... late to the party. I never put the transmission in gear until the idle is ~750 RPM; usually ~30 seconds if the engine is cold. If the engine's warm already, the 5-second rule applies. Also agree about not shutting off an engine that has been run hard, without it letting it 'settle down' or normalize at idle.
Cheers,
Jeff

Thanks for the advice guys I actually heard the same thing from other people wait about 30sec then take go but take it easy until the car is fully warmed up. Lots of people said its bad for the plugs and cylinders if you let it sit and warm up when cold.

As long as you dont redline it right at startup, and start doing 1/4 mile runs, theres no need to worry

The 'bad for plugs / cylinder' comments you've heard are probably hold-overs from the era of old school muscle-car engines. Modern power plants (and modern here is quite a few years) have been designed to be cleaner; less carbon deposited at idle and to a degree, self-cleaning after a mile or two.
Cheers,
Jeff

The bad warm up idea started with the carb engines. With the choke on engines were running rich and the extra fuel would wash the cylinder walls with raw gas thus removing the oil lubricant. With fuel injection this is much better controlled and now you are just wasting gas with a long warmup. So 30 secs and then easy drive threw the gears and on down the road is the best. Putting a load on it really helps to get it up to temp faster and the quicker it is up to temp the happier your engine and all the running gear will be.

i just feel a class of guilt when i dont warm her up.. but then i ask myself, "the engine will warm up either way, maybe one day it will turn cold and die? blah."

i just wait til the cold start drops to normal idle - or until i finish a half cup of coffee?