skim7x

I know not to really push the engine hard before the temp gauges turn white in the AMG display, but does anyone warm up their cars in the morning on cold start before setting off? ie remote start the car a few minutes early regardless of the outside temperature with the intent of warming the engine up, or sitting in the car for a few minutes with the engine running before setting off?

yetman

I do not warm mine up, before driving off. I thought I read somewhere that Mercedes Engineers do not recommend warm up periods but, I may be mistaken about that.

Dthquazi

Warming a car up with idling is an old practice. The most I usually warm my car up is to let the RPMs drop during initial start up. Then I will not push the car until fully warm.

It has been proven then idling your car for warm up is actually harmful and should be avoided. By driving the car, you get the fluids flowing quicker and better. Also, with the merc, you don't really accomplish much warming up by letting it sit and idle. The car will warm up a lot quicker with gentle driving.

skim7x

That's my philosophy as well. With my previous car I let the car sit just until the revs dropped to idle and then gentle driving after that... Who knows if that even makes a difference -- probably not, with today's engine and engine oil technology. Just wanted to get other thoughts on this forum. Thanks for the replies!

roy777

The manual says don't warm it up. Just take it easy until warmed up.

sean1.8t

Yep yep.

If you like your motor, you'll start driving it after the cold start is over. Letting the car sit there for minutes on end isn't going to kill the car in all reality, but it is very much harmful. These cars are designed to warm up with [gentle] load on the motor.

If you want to get your car warmed up quickly the right way, look into a block heater. Having one of those is the ****! After just 60 seconds of driving you pretty much have full heat!

l3m

+1. By driving the car, you warm up the transmission faster as well.

Mr. J

Last vehicle that I intentionally "warmed up" the engine on startup was '72 Chevy PU with a manual choke on the carb.

Otherwise, I'm just waiting for the windshield to defog before I drive off.

As a rule of thumb, I try to stay below 4000 rpms until the coolant temp is in the nominal rage. I wont ride it hard (red line, skipping gears, etc...) until after I've been cruising for a good 10-15 min. Engine and trans oil lag behind coolant a little bit in heating up.

Dthquazi

That is exactly where the warming up concept came from. It was for carbureted vehicles that would die if not properly warmed up.

sean1.8t

Only reason to pay attention to the coolant temp is if you don't have a gauge to monitor the oil. Therefore you're spot on with the "oil lags behind coolant in heating up" observations.

If you're oils are up to proper temp but for some reason the coolant is cold then go ahead and floor it if you want.


I really like having the transmission temp gauge. You can see it lag behind even the oil temp by quite a bit in most cases. I don't romp on the car fully until the trans fluid is up to temp.

Yup. My Harley does not like to move for at least ~5 minutes of "warming up".

ignomini

I don't believe warm up periods are recommended for any modern car. Turn it on, wait a few seconds, go. The electronics will not allow you to over do it until the car warms up sufficiently to be safe. Logic dictates, wait until you see some temp before flooring it. Simple.

I have used remote start to reduce the time before the ice melts on the windscreen. Don't like doing that, but hate scraping even more.

GEARS5

If they don't recommend warmups, then don't give us remote start!

Dthquazi

Apparently, for most of the people complaining the app doesn't work, they didn't.

GEARS5

The "Mercedes-me" app sucks.

I use the "M-Bmbrace" app instead... works great!

Dthquazi

I agree it sucks but it was what was setup and works perfectly for me.

I haven't looked into the Mbrace app yet and probably won't until I have to. I honestly don't use those features all that often anyway.

skim7x

Yeah I was initially excited about having remote start, but really stopped using it after realizing that 1: I didn't like the car sitting there idling while cold, and 2: I didn't like that the engine cut out when I opened the door only to have to essentially cold start it again... Just more wear and tear that just isn't necessary. I feel the same about the auto start/stop... On a v8 with 500hp, auto start/stop is, at best, like drinking a diet coke with your 3/4lb cheeseburger and value size fries...

All that said, the app works fine for me, as do all of its functions.

Dz1ur3x

Warmup is not reccomended. It's quite simple. While idling the engine uses only enough fuel too keep it running. When you drive, the engine is under load so it uses much more fuel. More fuel equals more heat which leads to quicker warmup. Other thing is that cold oil is very thick and doesn't do much of it's main job. In this case here comes the fuel which is a liquid itself and does create a thin film on the walls of the cylinder. That' why LPG powered cars need to start and warmup on fuel cause lpg is dry. The thing is to wait revs to drop down which usually takes up to 30 seconds. That's enough to bulid up the pressure of the oil and get any lubrication to the engine's moving parts and most importantly the turbos.
If you ask me: keep it under 3500rpm and try not to spin up the turbos, so just take it easy on the throttle (no flooring to those 3500rpm limit )
As for the temps... well in case of my c43 when the coolant is around 90 C the oil is still around 40-50 C but that should be enough to normal comfortable ride. If you want to push the car to it's limits always wait for the oil and transmission temps to reach their optimum.
And of course, those rules don't apply to any life threatening situations. If it can save your life... floor it.

BallzOne

You really don't even need to wait for the higher revs to drop down after start. The only reason cars do that is to try and get the cat converters up to temp more quickly for emissions. It has nothing to do with circulating lubrication. Oil is circulated everywhere it needs to be almost instantly after startup.

sean1.8t

Very true.

Once my ECU gets back (friday), I will be purposely stopping the "cold start" revs since now my cats ran away

skim7x

Thanks for that information -- I had no idea that cold start (high revs for about 30 seconds) only had to do with emissions and heating up the cats rather than spreading lubrication... good info

Dthquazi

This isn't always true...

I'm assuming people here keep up on their maintenance and use synthetic oils. So if you do, it should be fine to not wait the full time with the higher revs. I would still wait 5-10 seconds before driving off. Yes you have oil pressure through the block instantly, but that doesn't mean the oil has spread and coated everything.

If you don't keep up well with the maintenance, the oil will be affected. As oil gets older it gets "thicker" and takes longer to circulate.

Cold weather can affect the oil as well. Also the viscosity makes a difference. Dino oil breaks down quicker and loses its original viscosity quicker than synthetic. So if you are close to an oil change interval, the oil will not flow as well. Also the time between the last start plays into it as well.

I know the original intent was to say that you can drive off during the warm up, and I generally agree. I just don't want it to be interpreted as fire it up and go. Also using synthetic oils with the correct viscosity and getting oil changed at the recommended intervals is very important.

skim7x

Makes sense. I think the best compromise is just to sit through the initial cold-start phase, and as soon as the revs drop, start gentle driving... I think everyone can agree on that...

skim7x

Jerry beat me to posting this video -- he posted it on the front page, but it's a great explanation for warmup. Just thought I'd share for those of you who didn't see it on the front page.

Sanch

I always let my car run idle for a few seconds before driving.

I'm usually on the AMG screen and it will tell you the oil temps - take it easy until they all turn white (blue- they are still warming up).

TexasBenzBandit

I always wait until my Oil Temp gets to 150 before I get on it.