# Diesel warmup time?



## ljgmdad (Feb 2, 2012)

Hi folks,

Brand new 335d owner here with a question for the diesel gurus... What is the recommended warm up time for our engines? I.e. how long to let the car idle in the garage on a cold morning before driving off?

Thanks!


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## BB_cuda (Nov 8, 2011)

*Not long enough for heating interior with engine heat*

I read in the manual that our Ds have an electric heating element to suppliment heating via engine's hot water. It says since a diesel is more thermally efficient, that it takes longer to warm up as compared to a gasoline powered engine. So, until the engine's coolant system warms to XX degrees, the electrical element warms the air going into our compartment. Thermal efficiency means how much of the fuel is converted into engine output vs waste heat that warms the engine.


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## 4pipes (Aug 4, 2006)

Zero warmup time....just start and drive.


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## Snipe656 (Oct 22, 2009)

Really all modern cars should have zero warm up time. Many people are saying leaving a car idling to warm up will cause more damage to the engine and some say even to automatic transmissions. I personally don't buy into it causing engine damages because I am notorious for letting my vehicles idle upwards of 30-60 minutes in the mornings before I actually leave. My long idle warmups though are not for any reason outside getting delayed leaving the house but a sub reason is to get AC or heat going for the cars parked outside. My BMW and MBZ are exceptions to my routine because they are garaged and I just start them up and leave before my seatbelt is on.


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## Penguin (Aug 31, 2003)

4pipes said:


> Zero warmup time....just start and drive.


But, I would add, drive easy and gentle until it warms-up a bit.

Somewhere here or on xoutpost there's an old post I made which provided temperature data for a warm-up curve from a near zero overnight, cold-soaked start.

... found it, post 13 in this thread:

http://www.bimmerfest.com/forums/showthread.php?t=504303&highlight=carchip


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## m6pwr (Jan 26, 2008)

Owner's Manual says, in several places, that oil will be up to op temp in 6 miles (pretty quick). Wouldn't recommend warming engine by idling (that's actually a good way to cool down engine). Drive off straight away and drive gently until engine is up to temp.


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## DnA Diesel (Jul 31, 2010)

Only long enough for the ceramic heater element to defrost the windshield if there's any frost on the inside...otherwise, pretty much about 30 seconds after startup, keeping then engine below approximately 2500rpm until I've driven a few miles.

My coldest start ever was -42ºC (-45ºF) north of Timmins, Ontario, in January...1 second for the glow plugs, then turned over like a champ and I started driving about 20-30 seconds later - thank gos for heated seat and steering wheel!


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## Snipe656 (Oct 22, 2009)

Anyone ever experienced their car to be sluggish in reverse after a cold startup? It is not consistent with mine but it has happened more than once. Basically start it up, put on the seat belt and put the car in reverse, then start to easy up off the brake pedal for it to move but the car goes no where, take foot of brake and still nothing, apply some throttle and starts to move. I mentioned it once to the dealer and of course they found nothing.


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## Flyingman (Sep 13, 2009)

I start-up and it will idle about 1 min before going in gear. Lets me set up the car, GPS, radio, etc...

Then I have about a 4-5 mile slow (40-45mph) ride to freeway. I've monitored the cooling water temp on my Garmin Ecoroute and it reaches the 190deg within first few minutes. i do live in S. Fla. where temps have been nearly 80 deg all winter so far this year!

Once I hit the last greenlight I gun it to the on ramp and then open it up to near 100mph as I glide back down to 85mph and settle into the far left lane morning commute.:thumbup:

Never look back!


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## Snipe656 (Oct 22, 2009)

If you did not scramble your gps and radio the night before then you could save 30 seconds in the mornings


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## listerone (Jul 21, 2009)

In very,*very* cold weather warming up for a minute or two isn't a bad idea...then drive it gently for a few miles (no high revs,etc).Other than that I let mine idle for about 15 seconds then I drive gently for a mile or two.Be aware that letting a diesel idle to get heat and/or defrosting is a waste of time....diesels are very different from gassers in that respect.


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## Snipe656 (Oct 22, 2009)

I'd not say it is a "waste of time" it certainly works just takes a very long time(if you do not have any sort of electric aux. heater like the BMW and MBZ diesel cars have). I routinely leave my truck idling and partly to get the heater or AC going, it is nice and toasty inside the cab when I finally get into it.


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## listerone (Jul 21, 2009)

DnA Diesel said:


> My coldest start ever was -42ºC (-45ºF) north of Timmins, Ontario, in January...1 second for the glow plugs, then turned over like a champ and I started driving about 20-30 seconds later - thank gos for heated seat and steering wheel!


Well,you've got *me* beat.My coldest start was -31F early last year in Val d'Or,Quebec.One second of glow plugs,started like a champ.Let it idle for a minute or two (I'm not as brave as you) and then drove it very gently for about 20 minutes.But DAMN...for the first half hour or so that thing sounded like,and rode like,a Mack truck.I guess all season tires don't like temps that low even when you properly adjust the tire pressure for such temps (which I did).


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## listerone (Jul 21, 2009)

Snipe656 said:


> I'd not say it is a "waste of time" it certainly works just takes a very long time(if you do not have any sort of electric aux. heater like the BMW and MBZ diesel cars have). I routinely leave my truck idling and partly to get the heater or AC going, it is nice and toasty inside the cab when I finally get into it.


Well,we're talking Texas vs New England.You guys down there don't even know how to *spell* the word "cold". 

And I know it's also true that *we* don't know how to spell the word "hot" so A/C is a different kettle of fish.


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## Snipe656 (Oct 22, 2009)

listerone said:


> Well,we're talking Texas vs New England.You guys down there don't even know how to *spell* the word "cold".
> 
> And I know it's also true that *we* don't know how to spell the word "hot" so A/C is a different kettle of fish.


True although I have been in some rather cold weather in Lubbock where I routinely travel. But I'd imagine it still is nothing like up there. I can recall many a morning though going out to start my truck there and for one both batteries barely had enough to get it to start up, then number two the engine sounded like marbles and felt like it if you drove it but three the ice was so thick on the glass it was not like you were going anywhere anytime soon since in Houston you do not keep items in your car for scraping ice off. Oh and there was tons of this crazy white stuff on the ground/roads/cars there, I guess it was cotton but it sure was cold to touch.


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