[pard68]

Is that something that actually happens to diesel engines? I have multiple diesels and while they are difficult to _start_ in the cold they are fine once started for me. But yes, cold enough and combustion engines are hard to get going. My Subaru hates cold days, it'll go a few seconds on a below freezing day before ignition. My diesel tractors actually have electric plugs to keep the manifold hot.

[BenjiWiebe]

The reason diesel doesn't usually gel is that, starting in the fall, fuel stations/refineries start adding anti-gelling agents to the diesel.

If you have "summer diesel" in your tractor during a cold spell, it will gel. And a block heater won't help, since the fuel gels in the fuel lines and tank too. And trying to start the engine pulls in that gel into the fuel filter and sort of strains the chunks out, causing your fuel filter to need to be replaced even once it's warmed up.

I'm not sure at exactly what temperature it happens, but a Kansas winter will typically gel summer diesel at least a couple of times.

[rlkf]

Mostly it's the start battery that have problems in the cold. The diesel sold in Norway have anti-gelling substances added; cars run fine in -20 degC/-4 degF.

[pard68]

I live in the southern USA. So it makes sense that I have never heard of this. We had a -6°F night the other night but usually it'll freeze at night and be back above freezing by noon.

[maxerickson]

It's likely that the stations around you switch to a winter mix.

[bluGill]

diesel starts gelling at warmer than water freezes.

[bluGill]

number 2 diesel fuel will turn to jelly at a bit over 40f. That is warmer than water freezes. Number 1 diesel will be fine to well below zero, and you can mix them to get different gel points. There are also anti gel additives you can add to prevent gelling. Number 2 diesel has significantly more energy than number 1, and is also cheaper, so you want to run number 2 if possible.

[stephencanon]

Not anymore, at least in milder “extreme cold”. We live in northern New Hampshire, and never have an issue with our 328d wagon parked outside in -25F. It has a heater for the fuel line, and they add anti-gelling agents to diesel in winter.

[tim333]

It is an can be a pain for non diesel drivers if large trucks grind to a halt and block the motorway. That's happened in the UK in unusual cold spells.

[pard68]

Yes that'd be quite a problem. Our cold lasts so little here that I've never had a need to start any of my tractors in the freezing, just wait a day and it's back to warm.