Damn, car almost did not start this morning in Vail -temp was 9 degrees. Glow system is perfect, battery was strong (this car always starts) and I had winter diesel fuel in tank. What I did not do was plug the block heater in the night before -no outlet available! So engine was cranked about ten -twelve times with no fire! Fortunately, a guy next to me allowed me to jump off his truck which helped but for a while, I was beginning to think that my always highly reliable OM617 was not going to start ('82 300SD)

So hey cold weather brothers, what are your cold start tricks when in dire straits?

What weight oil are you running and when were your valves adjusted?

How old is the battery and how fast did the starter sound like it was spinning?

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-Typos courtesy of my mobile phone.

valves adjusted 3 months ago - oil is delo 15/40 and battery initially aqllowed for a pretty fast crank speed though synthetic would allow for faster cranking speed

Check your battery. Mine will allow almost 1 - 2 minutes of cranking before needing a jump 850cca. I also have 15/40. Most parts stores will check it for free.

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

Jeremy types faster.

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

If your battery is good you can try multiple full glow cycles before starting.
The 82 240 needed 4 rounds of 3 glow cycles before it would reluctantly start in single digit weather. Of course had it been plugged in it woulkd have started immediately.
Turn up your idle speed also when cold starting.

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

At what ambient air temperatures are you getting 1-2 minutes of cranking out of the battery? The OP stated his was in the single digits. If he left it in the car overnight he will get much less than 1-2 minutes cranking time, especially if he glows longer. In cold weather (cold to me is below 15F) I probably get 2 maybe 3 shots at starting it for maybe a total of 30 seconds of total time. If I glow multiple times it may only be one shot before the battery is drained too much to turn the starter fast enough.


To the OP-

Lighter weight oil will help the engine spin faster and thus start easier in these colder temps.
Also, how long do you glow for? The FSM states to run a full glow cycle to aid in cold starting. The light goes off but the relay stays on for a bit over 30 seconds, then try starting it. Some people even do double glows by turning the key back off and then glowing again after the relay clicks off one time.

At 9F you should be able to easily start a healthy engine. I have cold started mine in -5F. I think the lighter weight oil really helps.

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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 intentionally left my 300 outside last Saturday night just to make sure everything was OK. Next morning was 9 degrees. It started in about two revolutions with one glow cycle without touching the throttle. This was on a 6 year old battery, but with Amsoil 5/40 European car oil. Makes me wonder what its limit is- hope I never have to find out.

If you cannot run an extension cord to the car, consider removing the battery and taking it inside overnight. (A cold battery has only about half the capacity of a warm one.) Put the battery on a trickle charger. In the morning you will have a fully charged warm battery to put back into the car and it will be much more likely to start the engine.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

great tip Jeremy -next time I will put a spare battery in trunk which I will keep inside with me

Do you let the glow plugs run for the full 35 seconds that the relay allows, or do you try to start it after the glow plug light goes out?

How old are the glow plugs? A cold resistance check simply shows they all work, but there is a big difference between a red glow and white hot...........especially when you need it near zero degrees F.

You already know that 15W-40 doesn't cut it at these temperatures, and, yet you continue to use it. You do know the definition of insanity..........???

Ok so I need to change out to 5w40. I have had some trouble starting the old 300SD with the temps in the single digits. I also need to let the glow plugs run there full 35sec. I have found that the block heater is kaput and there is no way it is getting changed anytime soon. What do You guys think of a lower rad hose heater? I have to change the thermostat and flush the system anyway. The valves were adjusted 6k ago and it has always started good down to 12-15 deg. The battery was new in july. I have good cranking speed for a minute or two in 15 to 20 sec. cranks.

Lower radiator hose heaters are good.
However, the MB instructions are clear, you don't want to crank the engine in short bursts. You should keep cranking it until the engine starts or the battery is dead. Multiple short bursts are counterproductive to starting in very cold temperatures.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

You don't want to fry the starter though. I crank for 10 seconds at a time, then glow again a few times.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

MB designed the starters to run for long periods of time in cold weather. The MB manuals say to keep cranking it until it starts and to use the starter to keep it running on a few cylinders until enough are firing to keep it going. Gassers are a different matter.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13