MBSebas87

So every morning I start up my C and let it idle for 5 min for the engine to warm up.....is this good for the engine? Read somewhere to just take off after start

MDMercedesGuy

It isn't efficient, and it doesn't help your engine warm up much. These engines are so efficient that they don't make much heat at idle.

The best thing for your car and for the environment is to start it up, let the idle equalize (15-20 seconds) and drive off. Keep it under light load until it gets up to operating temperature.

The ultimate goal is to get the vehicle warmed up to the point where it enters closed loop mode and is running at its most efficient state.

w204_Generic

What about once you reach you destination? Should you leave the car idling for about 3-5 minutes or so to let it "cool down," or will shutting it off immediately after putting it in park will do just fine?

Another question is what would be the optimum oil temperature, in which you can start driving you car a little more "aggressively," than gentle driving to reach the temperature? Keep in mind the quotes around aggressive.

MDMercedesGuy

As far as idling down - I'd say only if you have been driving it hard. I have a turbo, so I do tend to idle down for 2 or so minutes if I have been sticking my foot in it a bunch. It's not really necessary any more with modern turbos, but I figure it can't hurt.

As far as oil temperature goes - that's a really good point. Engine coolant temp being up to full temp doesn't mean that oil temp is there yet. I don't have my scangauge any more - but I'd imagine 5 or 6 minutes after the coolant temp levels off the oil is good to go in these cars.

Not sure if the V6es are this way - but the 1.8 puts off so little waste heat if you aren't driving it hard that running the climate control severely impedes its ability to get the coolant temp to the point where it levels off if you are in stop and go traffic if it is cold out. In fact, during this latest cold snap my car wouldn't get over 80*C in a 25 mile highway drive with the cruise on and the interior climate control set to 68 for both sides - it was about 15*F out.

spyked

Keep in mind...in many places it is also illegal. lMany people have received tickets over the last few days around here. So many that it's on the news. It's definitely bad for the environment in terms of wasted fuel and the worst kind of emissions.

But in terms of the car itself....it doesn't DAMAGE anything until you drive it like you stole it thinking it's "warm" when its really not. Idling doesn't warm anything but the atmosphere.

MBSebas87

lol

MBSebas87

got the answers i needed..thanks!

robnyc

I agree I've been checking my car's temp this month that's been the coldest 10-30F and notice the car doesn't warm up at all when its idle. But warms up right away as soon as I drive off slowly. No more idling for more, but this is very different compared to my dads 2002 Toyota Avalon and 2007 Toyota Camry those cars warm up idling and i think it hurts those japanese to drive off cold.

JaredP

I let mine idle for a minute or so, then drive off being very light on the throttle. My V6 will cool down when driving in traffic only when it's below -30C or so.

AMG Boost

I idle my cars for 5-10 minutes before I drive in winter time. My reasoning for this is that in the cold weather the oil is very very thick, like honey. I idle it to warm up the oil and distribute it through the engine properly. Idleing is the lowest RPM the engine will spin at, so therefore this is where the least damage should be caused by the thick oil. If I was to drive off after 30seconds I would be doing theoretically more damage because I am increasing the RPMs....

Just my thinking on that.

Here is a cool video showing what extreme temperatures will do to engine oil:

Quadcammer

First, yes, negative 32C is -26 degrees farenheit and thats very cold. But if you note, the 0w oil flows pretty well. Hence the 0w-40 most people run in their MB. If you regularly see these temperatures, you likely could benefit from a block heater.

2nd, placing the engine under load, even at fairly low rpms, ensures that it heats up quicker and the oil thins out. By idling, you just prolong the period of time that the engine runs with cold oil.

3, most critical engine parts, such as the cams, main/rod bearings have an oil film, even after sitting for quite some time. this, combined with the fairly quick flowing 0w oil, means you should be just fine to start it, idle for about 30 seconds, and drive away.

lastly, this wastes less gas and also warms up your transmission and differential oil.

Quadcammer

m1 0w-40 is the third from the right when flipped over. Even at -11F it flows pretty quickly. keep in mind this is only gravity not pressure fed.

Sportstick

Paging Dr. Ruck.....Dr. Ruck to the forum thread, please!

KCaudell

Thanks for the oil flow videos at cold temperatures. Cool. It makes an important point. In cars that I've had that have oil temperature gauges, I've found that cars don't come up to full operating temperature until after about 15 highway miles. It takes longer than you'd think. MDMercedesGuy is spot on, coolant temperature is not a good judge of when you can drive more "aggressively".


I believe the best thing you can do for your car is drive it everyday. Be gentle until it's up to temperature (± 15 miles).


My 2¢!