# 535d cold start at -10F, X5 35d cold start at -12F



## n1das (Jul 22, 2013)

We had a cold snap over the past weekend and I had an opportunity test the cold start ability of my 535d and E70 X5 35d. Was surprised there wasn't any preglow time before cranking. Both cold started just fine. No need to worry about BMW diesel cold starting in the bitter cold.

535d cold start at -10F after being parked for a week and a half:
https://www.youtube.com/watch?v=h4yh5aLwB8k

X5 35d cold start at -12F after being parked for 10 hours:
https://www.youtube.com/watch?v=8QqyKpB2OPs

I shot videos of them for the 2016 IDparts.com Cold Start Contest.
http://www.idparts.com/news.php?articles_id=32
www.IDparts.com


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## Doug Huffman (Apr 25, 2015)

The pre-glow is 'concealed'

Concealed heating
Preheating and start standby heating are activated as so-called concealed heating up to a coolant temperature of 30 °C. Concealed heating is triggered a maximum of 4 times and is then not enabled again before the engine is restarted.

Concealed heating is triggered by the following signals:
***8226; Driver's seat occupancy
***8226; Driver's seat belt buckle
***8226; Valid key
***8226; Terminal R
***8226; Clutch operated.

page 112, Advanced Diesel with BluePerformance 
https://drive.google.com/folderview?id=0B1epIteFE7i-SG9xSTVEdVFPQlU&usp=drive_web#list

Coolant temperature in °C Preheating time in seconds
................< -35..................................... 3.5
...................-25..................................... 2.8
...................-20..................................... 2.8
....................-5...................................... 2.1
.....................0.......................................1.6
.....................5.......................................1.1
...................30.......................................1.1
................> 30........................................0


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## n1das (Jul 22, 2013)

Interesting....was not aware of concealed heating, unlike my VW TDIs years ago. In my TDIs I definitely could tell when the GPs operated prior to a cold start. I'm aware of afterglow occurring following a cold start, whether or not there was any preglow prior to the start.

BMW seems to have everything figured out well enough that the whole process is essentially transparent. They actually start better than most gassers do in the bitter cold. No need to worry about cold starts! :thumbup: I've had a number of people (gasser drivers) ask me how my diesels start in the cold weather and I shot the videos for the 2016 IDparts (www.idparts.com) Cold Start Contest so I thought I'd share.


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## NickTheStick (Feb 16, 2016)

@Doug Huffman Are you sure? I swear in my E90, in Chicago (dead of winter), I have seen a pre-glow indicator pop up at a cold start.


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## Doug Huffman (Apr 25, 2015)

NickTheStick said:


> @Doug Huffman Are you sure? I swear in my E90, in Chicago (dead of winter), I have seen a pre-glow indicator pop up at a cold start.


'Concealed' is their BMW word and there is no indication in the referenced description of an indication or not. YMMV RTFM ETA: Note the maximum time, 3.5 s

Milady Wife glares at me for not waiting for her to be settled before starting. I START the engine smartly on entering, before seatbelt and before she may even be in the door.

My '03 TDI started reliably at -25°F and once that I recall at -35°F when it grumbled.


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## Doug Huffman (Apr 25, 2015)

n1das said:


> [ ... ] I shot videos of them for the 2016 IDparts.com Cold Start Contest.
> www.IDparts.com


*IDparts.com* is where I bought my TDI timing belt kit and oil change kits.

I note your 1000 RPM idle after cold start.


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## n1das (Jul 22, 2013)

In the videos you can see I didn't spend much time in the seat before the cold start. Maybe I should have just opened the door and reached in and pressed the brake pedal with one hand and press the START button with the other. It's kind of hard to do that while holding my cell phone to make the video.

Bottom line is BMW has it all figured out well enough that you don't need to do any tricks like double glowing an old school diesel before hitting the starter.


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## n1das (Jul 22, 2013)

Doug Huffman said:


> *IDparts.com*
> *I note your 1000 RPM idle after cold start.*


It was definitely telling me it's COLD out!

The 535d didn't really sound much different right after the start. The X5 35d OTOH sounded a bit angry and more dieselly for about a minute following the cold start.


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## Doug Huffman (Apr 25, 2015)

So you don't read the concealed heating triggers as causing three glows, one for seat detector, one for valid key and one for Terminal R (that may be START)? But, yeah, transparent. I'd rather be able to follow the process logic. Heck, I cant even see coolant temperature without tinkering, never mind DPF condition.

I will be SO relieved after a couple of hours at 70 - 80 mph on Thursday.



n1das said:


> In the videos you can see I didn't spend much time in the seat before the cold start. Maybe I should have just opened the door and reached in and pressed the brake pedal with one hand and press the START button with the other. It's kind of hard to do that while holding my cell phone to make the video.
> 
> Bottom line is BMW has it all figured out well enough that you don't need to do any tricks like double glowing an old school diesel before hitting the starter.


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## F32Fleet (Jul 14, 2010)

NickTheStick said:


> @Doug Huffman Are you sure? I swear in my E90, in Chicago (dead of winter), I have seen a pre-glow indicator pop up at a cold start.


This. My 2010 335d would flash the glow plug indicator in these instances. IIRC they also fire when cold, w/out the indicator but when it was really cold I would get the indicator and perhaps a 1 second delay to ignition.


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## robster10 (Oct 8, 2012)

Well I didn't video it but this weekend the D started up without a hicup. We had a cold snap with Saturday hitting -26c & Sunday -36c. -36c is -32.8 F with the conversion.


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## mefferso (Feb 26, 2014)

@n1das...cool videos. And man, you've been putting some miles on your X5 35d. I saw you have 117k on it. Many issue thus far? Thinking about getting a higher mileage one for my wife.


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## FredoinSF (Nov 29, 2009)

Great stuff, love that you're driving these cars and putting lots of miles on them, but what the heck are you doing starting these cars in the dead of night?? And on VD too!!

FWIW I've seen the glow plug light flash. I wonder if glow plug routine is triggered by unlocking the car and / or having the welcome lights on (auto headlight mode). My car is usually unlocked in the garage with headlights in off position at the cold weather house, so maybe the glow plugs don't kick in til I'm in the car pushing the start button? It still starts instantly so not losing sleep or starting a debate over it, just reporting I've seen the symbol. 

Either way, great frigid weather startup performance, particularly the 5er.


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## Doug Huffman (Apr 25, 2015)

FredoinSF said:


> [ ... ] . I wonder if glow plug routine is triggered by unlocking the car. [ ... ]


Would that constitute a "valid key" from the list above?


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## Enthusiast 456 (Jun 23, 2014)

My gp light comes on no more than 3 seconds, even at 10°F. This is on a 328d so glad to see BMW has this figured out across the line.


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## n1das (Jul 22, 2013)

mefferso said:


> @n1das...cool videos. And man, you've been putting some miles on your X5 35d. I saw you have 117k on it. Many issue thus far? Thinking about getting a higher mileage one for my wife.


The X5 35d was bought CPO in March 2014. Drove it off the dealer's lot with 52k miles on it. The first owner basically threw a perfectly good car away as soon as the original factory warranty was done and free service ended. It worked out good for me since I plan to be into it for the long haul. Now at only 118k miles 2 years later. My 535d was bought new in 2013, ordered 1 July 2013 and delivered on 14 August 2013. My order went into the system about 24 hours after it first appeared on BMW's website. I was watching and waiting for it to appear and be able to "build your own" on the site. I went to my BMW dealer the next day.

I am the only driver of my vehicles. I drive around 1k miles/week and 100k miles represents a little under 2 years of driving for me.

Both cars are running great. No issues with the 535d. I had some sensors (MAF, boost pressure, and NOx) mysteriously fail all at the same time around 95k miles and threw it into limp mode. Was quickly fixed by my dealer and covered under CPO warranty. The X5 35d has been perfect since.

Cheers.


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## jfxogara (Oct 26, 2012)

NickTheStick said:


> @Doug Huffman Are you sure? I swear in my E90, in Chicago (dead of winter), I have seen a pre-glow indicator pop up at a cold start.


Second that on my 2011 335d, on super cold days. Just a flash of that little curly pigtail. Still these cars are in another universe from my 300D, which was one-Mississippi, two-Mississippi, three-Mississippi etc even on warm days.


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## n1das (Jul 22, 2013)

FredoinSF said:


> Great stuff, love that you're driving these cars and putting lots of miles on them, but *what the heck are you doing starting these cars in the dead of night??* And on VD too!!


It was a once a year opportunity to get a data point for each car. In retrospect I think I should have waited an hour or two longer before attempting the cold start.

I made the cell phone videos to enter them in the IDparts.com 2016 Cold Start Contest.
http://www.idparts.com/news.php?articles_id=32

BMW diesel cars start great in the cold weather. They actually start better than most gassers do in the cold. No worries about winter cold starts.


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## Doug Huffman (Apr 25, 2015)

This am we headed south for SC, and had to finish packing the X5 ungaraged for the too tall bikes. I got in and fiddled with arranging stuff, and then hit the START to see the curlicue and a one second delay to the starter.

And I watched DPF regeneration on fuel mileage. GD headwind killed mileage worse than the bikes. Normal, I'll.


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## John Galt (Jul 21, 2012)

I live in MN and travel extensively in the Dakotas. The coldest I had started my F15 35d was -37 below. Jumped in, hit start, the engine indicated pre-heating in the instrument cluster and it fired right up. I let it run for about 10 minutes and off I went. I believe on that trip however I froze the sensor in the EGR system (can't recall specifically which one). Caused a CEL and the dealership said they had not seen this happen before. This was on my 2014 and so far my 2015 has been cold-weather-flawless. 

-John


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