I've started my 85TD at 35 below zero F without a block heater. It would not stay running because the fuel was gelled. I was told by the tow truck driver that he sees it a lot because Denver does not winterize diesel fuel. Mountain towns do by mixing #1 and #2 in various proportions depending upon the typical temperature in the region. I was surprised to learn this (if it is true).
I wonder if some of the starting problems we are discussing would be alleviated with proper fuels or additives. For instance, would straight #1 diesel mitigate the 'only get once chance to start' problem?

ten below zero yesterday. no block heater, sitting for 12 hours. fired right up on the first glow cycle. I have started her at -18 before, no block heater. now I have a circulation heater, but I forgot to plug her in monday night when I got home at 1:30 am after a 280 mile RT.

5 new Bosch GP's this fall, 5-40 rotella, recent valve adjustment, and 400+psi compression makes all the difference. really its the oil that makes the biggest difference. no go at +7*F w/ 15-40 in it. but I was not a pro cold diesel starter at that point in time, either- my first winter with the benz.

my car eats glow plug relays...another relay died on me...


but I can start it in FL's cold of 30F (sometimes) without an issue.

I've started one of my cars as low as -20F.

This is from my factory owners manual:

Ambient temperature below 0 degree C

Depress accelerator to the floor. Turn key in stering lock clockwise to the stop. Release key only when the engine is firing regularly and back off accelerator slowly.

Do not interrupt the starting process. If the engine is very cold it is possisble that it will fail to start on subsequent attempts.

My the coldest I started my 82 SD was 9F. No garage, no block heater, and well over 300k on the clock. I had to keep my foot on the till it warmed up. That was after I changed the glow plugs. Before the GPs it wouldn't even start at all below 35.

The '95 doesn't seem to be phased by cold weather at all. Starts instantly at soon at the light goes out. (When I don't have gelled biodiesel in there!) It hasn't gotten down to 9 yet, but close.

Valve Adjust And Correct Oil !
 

Are prolly the two most important things as tight valves lower the compression right when you need it most and thick oil slows the cranking speed.....

Synthetic oils help a LOT .

What bugs me is all the stupid customers whi skip having the valves adjusted " they're FINE ! " then ***** when the car has cold start issues or misses ~ how the hell would they know if the valves are ' fine ' or not ? when they go tight , they're SILENT so you cannot tell...

A good running engine has valves that click like grandma's old sewing machine .

My 300SD fail to start at this morning
 

What gives, i had half tank of fuel with power service additive in it, and it fail to start, temp was 16*F, it started on that same temp every time but it struggles, i cycle my GP 3 times and start until it runs. :eek: but today it just wont, battery is probably getting tired of that long cranking, looks like i have to drive long and far for a while...

No garage and no block heater I keep a battery tender hooked into my battery to keep it warm overnight. I started my car in -30c (-22f) in a few seconds of cranking after it has been sitting for days. It was so cold my door wouldn't latch when I closed the door, it would bounce back open a few times.

While not a good thing, my 617 starts faster in the extreme cold than my wife's M103....well, maybe not faster, but about the same.

I'm tempted to wire up a float charger in addition to a block heater; that way I'd have a nice fresh battery and warm block in the morning :)

I wired a snap-on battery tender under my dash with a 120v relay to make contact when the car is plugged in. As soon as it's unplugged the relay opens and the battery tender is disconnected from the battery/alternator of the running engine. It is why I can start my car in our current weather. A strong warm battery makes a big difference.

Well I havn't really driven the SDL in the winter, but when I first got it I wanted to try so I left it outside unpluged and when I started it in the morning the dash temp guage was showing -2. I just turned the key when the GP light went out and it fired right up. I need to figure out whats going on with that car, its been starting poorly on new GP's. I'll have to see if they are actualy glowing at some point.

My 300SD never started well, that car was shot. I had to plug it in if it was going to be in the low 20's that night or it wouldn't start.

I think I found the threshold for my 240D starting. I plugged in last night and it started up fine at 10 degrees. Then it sat out in front of my work for almost nine hours (worked a little late:D) and tried to start it at 16 degrees. It coughed, but didn't start, and then I ran the battery down (didn't take long) on subsequent attempts. I used a 50 second glow on the unsuccessful attempt, and 60 seconds when I jump started it, so I think if I had done 60 seconds the first time, it may have started.

I've been getting excessive smoke on startup, and a little white smoke along with lack of power (hard to tell on a 240) even when warmed up, so I need to check a few things. I already know the tank strainer is clogged, but not badly, and I want to have my injectors tested. It also occured to me that I really should check the timing chain stretch. I forgot to do it when I adjusted the valves, and at the rate I drive the car, it won't be due for that service again for about three years.

I think it got down onto the 40s one morning when I pulled mine out of the garage.