Just before sundown on Christmas even I feed the birds just outside the garage and when I came back in I hit the down on the remote and stuck it in my pocket and somehow accidently pushed the button again stopping the door from closing any further. About 9:30 Christmas morning I went into garage to put trash in trash cans and discovered dooor open (about 2 ft) and the digital clock & thermometer reading 17* F in the garage and -3* outside. I have an insulated garage with a small oilfiled electric space heater to heat it in the winter and it was on at the low setting is probably only reason it wasn't colder in the garage.

Now for the funny part, the first thing I thought was will the MB start? We leave the keys in the cars, so I just opened the door of the 240D and leaned in turned the key to start and waited for glow plug light to go off then hit the starter. The car started on first compression stroke, and sounded like the verry devil running. Once oil pressure came up to max and it ran for a minute it started to settle down to normal noisy self.

Now this car has no block heater, but is running on 49 cetane B2 fuel. I think the high cetane fuel is the reason the car started so easy, that and having rebuilt the starter last spring. I guess a well charged battery helped also. I didn't check wife's car, because I've seen it start after sitting out in below -5 below zero weather without hesitation.

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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.

Actually I've started 123 diesels with no trouble at as low as zero F. If the glow plugs are working properly and the fuel is not geled it's no problem. Diesel, at least the grade we get in Texas, gels at 9 F.

It's all in the glow plugs and yours are obviously in good shape.

Have a great day,

I have a 1977 300D. People always ask me, do you have a block heater. I always tell them "the only place I need one is where I can't use it (at work)". I keep my car garaged so I don't need it at home and I find that even when the temp gets to single digits the old car starts even if it has sat for a day or so at work. Sometimes it takes a while, but it starts.

These cars really respond to maintenance, fresh oil, valves adjusted, fuel lines clear, good battery. If these and other things are in place, the I would imagine, based on my experience, it has to get bad cold for them not to start.

On doors open,,,, here's on for you. My teenage son didn't close the door well when he let the dog in before going to bed last week. When I got up to go to work, the front door was wide open and it was 6 DEG F outside. Thankfully none of the creatures in the woods that surround our house, including bears, stopped in for a meal and a warm me up. I bet I spent a $100 in oil that night.

JCD

Ouch!!!

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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.

I hate to disagree with the great Larry Bible, but I take strong opposition to this statement. THE most critical factor in starting a diesel is the compression of the engine. The colder the ambient temperature, the more critical the preglow system becomes. As a Wisconsin resident, I realize this. The original poster and I must be close to the same latitude. You may have some trouble starting a diesel with good compression once you get lower than 40 degrees or so, especially with a less-than-optimal battery. But I have seen worn-out engines give up the ghost, even with good preglow systems and battery, as "high" as 50 degrees ambient temp.
You may be able to get a strong diesel started without the aid of a preglow system as low as about 20F if the battery holds out, as the compression will help heat up the combustion chamber, even without the aid of combustion actually taking place.
If you have healthy compression, battery, and preglow system you shouldn't have to worry about ambient temps above 0F, if it gets lower than that, then things like garages (even unheated, if it is slightly warmer inside than outside) and coolant preheaters are a nice insurance policy.

Gilly

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I have faith in the glow plugs, they really do make a difference, I was formerly starting mine by giving it about 30 seconds of glow, then about 15-20 seconds of cranking when it was below 10 deg's out.....but I tried a new method, I simply sit and wait for the whole first glow cycle to end, then I quick start the cycle again, and after about 25 seconds into the second glow cycle I crank, usually less than 3-4 seconds of cranking/8-10 strokes and its running now! Glowing a lot longer makes a huge difference. Last night after work around 12:15am I did this extended glow procedure that I do now, and it was only about 2-3 deg's out, and the car was in a windy parking lot. 5-6 cranks and it was running. I also have the extended glow relay and a new set of plugs (as of july).

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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)

Well I'm quite a bit south and east of you shipmate.

However as much as I hate to disagree with Larry, I with you on this Gilly. Compression is probably most inportant thing when talking about starting one of these diesel's, next is fuel quality, glow plugs would be 3rd in my book. But if you have all 3 of those then these cars should start at -10 Zero F, they may sound & run poorely for a short period is only thing.

Flame proof skivies on.

After thinking about it a little more, I would say that all three are about equal in importance. If compression is low it effects starting, low cetane fuel will make starting difficult, especially the more of it you use, and good glow plugs do make a difference also. I had a 300D N/A that didn't have working glow plugs, had pool fuel, but it had good compression and it started easy in 70* F weather after sitting for about 10 days. Also on these old cars with starters that have had the grease in them dried are not the best when requiring some turning power. I had my starter pulled, cleaned and reinstalled this past spring and it doesn't drag when starting.

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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.

It's not possible to simply specify that:

"compression is the most important thing" or

"glow plugs are the most important thing".


The issue is simply the temperature of the inside of the cylinder when fuel is injected. If you have an engine with very good compression, you can probably start it without glow plugs down to maybe 32 degrees or so. Then, with the use of glow plugs, you can start it down to -10 or so, if the fuel does not gel.

If you have an engine with some miles on it, the situation is simply shifted. You can easily start it without glow plugs at maybe 75 degrees or so. Then, with the use of glow plugs, you can start it down to +10 or so.

Compression certainly helps with starting, but, a brand new engine from the factory will not start at 10 degrees without the use of glow plugs.