Coldest start survey
 

OK -- I don't know if this has been done before here, but thought I'd do a quick survey to see what was/is the coldest temp (Fahrenheit) they've been able to start --- WITHOUT a block heater, etc. assistance. (fuel additive is OK)

AND the coldest temp people have been able to start WITH a block heater...

thanks for your participation!

Sorta just did this. But with details on heater or not, etc.

http://www.peachparts.com/shopforum/open-discussion/311597-coldest-temperature-you-have-started-car.html

We haven't had any really cold winter this year. If we have a very cold night, I might pull W123 300D out and see how it does. It has been starting so well. A couple of years ago it sat out for 24 hours and I got it started with some difficulty at about 8 below zero I think it is running better now, I did an excellent job on setting the valves when it was out of the car and now I am using Mobil One and I was using dino oil in the past.

Had to start it -11 C 15w40 oil block heater not plugged in,, started ok,,
but I try to use block heater for any thing below 0 C,, I just want that oil to get warm faster.

IN Farenhight that would be +12.2

coldest I've started ANY diesel was in an unheated shop with it plugged in... -40... with massive wind, but like I said... it was inside...

my cars are southern cars now, so the coldest I"VE seen in them is around 10F... I've never had a block heater in them... so, they've started that cold without one...

3 degrees Fahrenheit, no block heater. Glowed one time with 20 seconds after light went out. Started up first time without repeated cranking.

OM617- 8*f after a month outdoors with 15w40, easily started on one glow plug cycle.
OM606- Only 20*f after 10 days of sitting outside, 15w40 and one glow plug cycle, started very easily.

OM617 in -13F outside, unplugged all night.... 5w40 synthetic oil. Glowed 3 full cycles then about 12 seconds of cranking before it would run on its own....and about 3 mins of high idle to get it to run smoothly. Thankfully it hasn't gotten that cold in a long time and its now plugged in most of the winter for the coldest starts of the day. Oil + coolant hose heater.

1984 300d...was 8 degrees this morning,started right up after one full glow cycle and a couple pumps of the throttle.....no block heater and straight diesel fuel...I was impressed anyway!

1983 300SD cold start temps
 

For my old girl:

Without block heater, I am confident of a start at -20C or -4F.

With the standard block heater plugged in, I've started without a problem at -25C or -16 F.

5W/40 synthetic oil, glow plugs in good shape, adjust valves at manufacturer recommended interval, Stanadyne fuel additive used year round. Nothing fancy, no special technique. Low mileage engine helps - only 160,000 kms.

1985 300d
 

My block heater is SNAFU.

So far this winter I've started it down to -24 C. Rotella synthetic 5w40 in the crankcase. Battery blanket.

I used a magnetic heater on the oil pan on the worst days but it didn't make much if any difference.

The biggest challenge has been that I have a massive air leak that at first only gave a problem under -15 C, but just as of this morning is giving me headaches all the time.

I suspect the primer pump, though it's the new style and I have never had one leak....

Having a new heater and primer pump put in Wednesday. My back is sprained and zero chance of working outside right now....