How cold before winter-blend diesel gels?

[Chris Blanchard]

As I was starting my 84 300SD on this extremely cold morning (-2F / -19C), I wondered at what temperature does the winter-blend diesel begin to gel?

I believe regular #2 diesel begins to gel at 28F or so, but have never heard anyone talk about the winter stuff freezing. I would think that it depends entirely on the mixture... but there must be someone out there familiar with the specs on the stuff.

BTW, my car started after two glow cycles and keeping my foot on the "accelerator". It didn't want to idle, but after keeping the RPMs at around 1000 or so for two minutes, it would grudgingly give me a rough idle.

After sitting there for 20 minutes, it sounded fine and the drive to work was uneventful.

This is the coldest morning since I bought the car two years ago. I'd wager that if it were another 10F colder it wouldn't start and I'd have to resort to plugging it in at night.

Chris Blanchard
1984 300SD 166k (starts at -2F/-19C!)