300D starts in -20C weather.
 

We have had some phenomenally cold weather up here. Our 85 300D had been sitting outside since before Christmas. Decided to use it today, and she started right up first time. No block heater and quite old battery.

Never always did this even after rebuild about 120k km ago. I did two things that I think might have helped:
- Tightened alternator belts. I think they may have slipped a bit under load and as a result battery never got fully charged
- Did a valve adjustment this past Spring.

Whatever reason, she starts and runs great! Even after owning for 27 years, still love this old car!

Remarkable. Should have done a cold start video.

You definitely have good compression. My 1985 300D started needing the block heater to start even in our mild winters (citrus trees, rarely freezes), and a couple glow cycles. I recall most cylinders measured <300 psig compression. The engine failed a year later (pistons lost chunks). But, the flipside isn't true since many things you mentioned can also make for hard cold starts.

Only 120k km on engine since rebuild in 2001 that included resleeving I believe. Compression should be good. Idles smoothly (for a diesel ;) )

-18C now and going down to -26C overnight then up to -16C tomorrow. Have to see how she goes in morning! Heading to SC in a week, thank goodness (in our other diesel!)

https://www.youtube.com/watch?v=PeHPQSnhyig
I think this guy should start off an episode were the drop off point would be an artic landing . the only way out is a cold start w123 ,that would be the video for all times.Might as well through in some polar bears in the distance and closing .

My cold start experience here in the deeper south never reaches those sub freezing conditions that you guys have to endure in the much northern states ,especially as a daily needed driver.I like to hear that these will perform well as long as a free standing mechanical glow plug system is in place.I believe whatever pre-winter extra measures are needed you northern drivers usually are prepared.Down south it usually catches us off guard in that a cold snap has us snapping too.

-24C this morning. Haven't tried car yet, but amazing thing is that our Heat Pump is still able to keep our house at 20C with no supplemental heating. Mitsubishi make a special unit for our type of climate (Zuba-Central). Amazing that there is enough heat in -24C air to provide heating! Solar probably helping a bit.

Are you using synthetic oil or a lighter winter weight?


Mine is a '98 which I've owned for 10 years. It has always started on the first turn of the key without regard to temperature. I have attributed that to synthetic oil.

I have used 5W40 Mobil TurboDieselTruck for quite a while, but I couldn't find any, so used something else. Maybe 0W40, but could have been 15W40. All either Mobil or Castrol synthetics. I don't usually drive this car in this sort of weather. It will soon be parked for rest of winter.

These old diesels have alot more trouble with cold weather than your 98. We have a 2014 diesel that hardly notices the cold weather,

Bad news is that after sitting outside last night and most of today (-26C), she almost started, but wouldn't keep going. Then battery ran down. I just left it - too darn cold to work outside hooking up charger and magnetic heater.

7pm - decided to out and plug in a charger!

Charging did not help. Couldn't find my magnetic heater, so bought a new one (C$69.99 :( ) Anyway left if overnight and started no problem. Mind you, it had warmed up a bit - Only -18C!)

Started packing the GLK to head South!

Here's a video my 85 300D w 168K miles cold start at 18F (-8C), 5W40 syn, battery fully charged, no block heater, 30 sec glow. Car has been cold soaking for 5 days. Started and idled pretty good.

https://www.youtube.com/watch?v=10D9CwnAFHo

I regularly would start my 300D in subzero temperatures without issue and without a block heater. This was fairly common weather temperatures in the mountains where I went to school.

I always did a valve adjustment once a year around Thanksgiving. I found that they would get really tight even after a year of driving.

I don't think a block heater is even necessary if the engine is in tune. Throwing in some 5w40 and having a healthy battery should be all that you need.