My car was parked outside overnight. When I went out there this morning I realized that the timer wasn't turned on. Usually it kicks on at 5am automatically but I was in a rush last night and didn't double check it.

So I decided I would give cold starting it a try. I got my stopwatch out and turned to the ON position to let it glow and started the timer. My temp gauge read -19.0C. When 30 seconds elapsed I turned it off and started over again. At about 25 seconds I started cranking and it fired up after only a few seconds of the starter spinning.

Out on the road I saw one bank saying -2F and another saying -4F. -19.0C equates to -2.2F.

I was pretty pleased with a start in that temp after it sat cold for 12 hours in below 0 temperatures. How easily it started made me think I could get it started at -10F.

Mobetta has told me he started his 300TD cold in -15F before. I think my SD has a shot at it, but I would rather not voluntarily try it.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

It sounds to me that you have a healthy engine and fuel injection system along with a good battery and starter.

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

Battery is one week old, replaced the starter in early December with a used working one (off of another engine), Valves adjusted to spec ~5k ago (in October), M1 5W-40 oil, 5 new Bosch glow plugs that were new with the valve adjustment.

After all the crap I went through last winter it sure is nice to have it starting in this cold of weather now!

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

i'm curious what type oil your using.
i just switched to 5w40 synthetic Shell and it made a difference in starting.
i also made sure the glow plugs were good and cleaned the contacts on the glow plug relay. it was 19F yesterday morning and even though i wasn't driving it, i had to try to see how it started. fired right up when the indicator light went off.
roberto

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1985 300SD
1998 Jetta TDI
Previous: lots of diesel VW's, MB's, KW's, Pete, Freightliner


Walking isn't a lost art: one must, by some means, get to the garage.

I would recommend always use the block heater in temps below freezing. 90+ percent of engine wear occurs at cold startup until a good flow of lubricating oil is circulating. At -3 degrees, your oil is like molasses (unless you are using a low-vis synthetic) and those pistons are sliding around dry and making metal shavings until the oil warms up.

J.G.

Like I mentioned, I didn't voluntarily do it. I had it plugged in but I didn't double check the timer. I always plug it in when I can below freezing.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

I use Mobil 1 Turbo Diesel Truck Synthetic 5W-40.

I know Mobetta uses Rotella Synthetic (well, the label says syn anyways- I know most say it is not a real syn but just going by what the bottle says) and he told me he cold started in -15F once.

From my reading on the forum, the switch from dino to synthetic oil is claimed to give 10-20 degrees colder of starting power.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

Just a general recommendation for others that may read this thread, and who may NOT regularly pre-heat in cold temps. Some people don't consider or understand the gravity of cold-start wear as you clearly do.

J.G.

Coldest I've started at was -13F.....its COLD!

Next week its supposed to be subzero here for a few days, we'll see how it does.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

ever the engineer my father takes his cars out of the heated garage
on the coldest days of the year just to see if they will start
Must be his version of a Polar Plunge

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commercial fisherman diesel in my blood in my boats trucks and Dear old Dad has had me drivin them since i got my first license in 1968
1986 300 SDL 427654
1999 Chevy Crew Cab Dually 225423
1986 300 SDL 287000 Dad's
1987 190 Turbo 158000 Mom's (my inheritance)

Glad your "new" engine is running like a champ.

yeah- I forgot to plug mine in last night, too- so I had another cold start. no problem on one glow cycle.

Man it takes along time to get cabin heat when it's that cold out. Brrrr- my toes were frozen when I got to maplewood.

FWIW- when I had to start it at -15(no block heater at that time) I was running Mobil-1 0-40 oil.( arctic diesel oil) I ran that the first winter before I added a block heater, and drained it come spring.

made all the difference. no start at +7*F w/ rotella 15-40, no problem at -15*F w/ M-1 0-40. yes, it is diesel rated.

also as of this fall, I have 400-425 psi across the board. that helps more than anything.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

timely thread. . .

last week Boston got down to about 10deg above F.

my daily driver is the 2000 VW TDI, and I have beed having some cold start issues (GP relay suspected). .

anyway the VW would not start. . .so I was forced to the M-B.

Fired up right away like a champ! (as an expermient I only glowed the plugs once) oil pressure came right up also. I use Total diesel rated full syn. same for the TDI.

the 87' got me to work that day! (I leave the house @ 5am)

you just can't beat a Benz!

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87' 300DT (Grey w/ red leather)
87' 300TDT (silver w/ palamino tex) SOLD

2012 VW JSW TDI (on tdiclub.com all the time "btcost")