Winterising Diesel

[NorthernRaider]

Winterising Diesel

From Bjørn Hall (Krøderbanen Railway Museum, Norway):
As a diesel train driver at the Krøderbanen museum railway in Norway, and working with repair and maintenance of preserved diesel shunters, railcars and DMU's I think that the following might be of some help.

Low temperature fuel problems is usually caused by two things; water in the fuel or waxing of the fuel. Waxing (if that is the correct name for it in English) means that as the temperature drops vax crystals form in the fuel, thus clogging the filters etc. The temperature at which wax crystals form in diesel fuel is called its cloud point, and the lower the cloud point the better for cold-weather operation.

Problem 1, Water in the fuel

Water in the fuel will give you trouble from 0 degree centigrade downward. Always keep your fuel-tank full to minimise condensation. Drain your tank often, exchange your fuel-filter each autumn, and drain them now and then during the winter. The filters will collect not only dirt but also water, and then they quickly freeze up on you.
Problem 2, waxing of diesel fuel

In Norway diesel units, and motorcars, are run all year round and in temperatures reaching - 30 degree. centigrade and lower. To avoid the waxing problems the oil companies in Norway deliver their diesel fuel in (at least) two temperature grades.
"Summer grade" with a minimum operating temperature of approx. - 11 degree centigrade, and a "Winter grade" with a minimum operating temperature of approx. - 24 degree. centigrade. When this is not sufficient the operating temperature is lowered further by mixing paraffin in the diesel fuel. This can be done with any grade of diesel fuel, i.e. your "summer grade" can be transformed into a fully functional "winter grade" by adding paraffin.

Based on information from Shell here in Norway the operating temperature of the "summer grade" will be lowered approximately 2 degree. centigrade for each 10% of paraffin. The effect with "winter grade" is somewhat better; approximately 3 degree. centigrade for each 10% of paraffin. This way the operating temperature of the "summer grade" can be lowered to
approximately - 25 degree centigrade, and the "winter grade" can be lowered to approximately - 42 degree. centigrade. Refer to table 1 for details.

IMPORTANT: Whenever mixing more than 40% of paraffin in your diesel you must add TWO-STROKE engine oil to the fuel. This is because the lubricating properties of the diesel is destroyed when mixing it with large quantities of paraffin, thus you risk excessive wear or breakdown of your fuel injection pump if not adding some two-stroke oil, whereby the lubricating properties is upheld.

When mixing diesel and paraffin it is not sufficient just to pour the paraffin into your fuel tank. If you do this the paraffin and diesel will not mix well. The paraffin will then end up as a layer on top of the diesel fuel. Either you should stir it thoroughly after pouring the paraffin into the tank, or you should pour it down into the bottom of the tank by means of a hose. Personally I would recommend doing both, pour it into the bottom of your tank through a hose, then stir it.
Table 1: Diesel fuel operating temperatures

Diesel fuel summer grade winter grade % of two stroke oil
opr.temp as sold -11 dgr. C -24 dgr. C 0 %
wiith 10 % paraffin -13 dgr. C -27 dgr. C 0 %
wiith 20 % paraffin -15 dgr. C -30 dgr. C 0 %
wiith 30 % paraffin -17 dgr. C -32 dgr. C 0 %
wiith 40 % paraffin -19 dgr. C -35 dgr. C 0 %
The following not to be used without the added two-stroke engine oil:
wiith 50 % paraffin -21 dgr. C -38 dgr. C 0,50 % t-s oil
wiith 60 % paraffin -23 dgr. C -40 dgr. C 0,75 % t-s oil
wiith 70 % paraffin -25 dgr. C -42 dgr. C 1,00 % t-s oil
If using diesel fuel with other clouding points then assume a lowering of the clouding point of 2 degrees centigrade for each 10% of paraffin.

Other measures

Use engine oil SAE 15W - 40 or 10W - 30 depending on climate. This makes for easier starting and reduced wear during the start-up and the warm-up period while you fully maintain lubrication at normal operating temperatures.

If not already installed then install coolant heaters on your engines. This will greatly improve the cold-starting abilities, and will also reduce wear. I think there are diesel fired systems available, but in Norway we use electrical heaters in the cooling systems of all our engines.

Always use ethylene glycol based antifreeze in your coolant. 30% will keep you safe down to approx. - 15 degree. centigrade, at the same time providing a sufficient corrosion protection. At the Krøderen line we use a 50/50 mix the year round, it keeps us safe down to approx. - 36 degree. centigrade during winter storage.

Hopefully this will help you with more trouble free winter operations. Some information about Krøderbanen museum railway and The Norwegian Railway Club is available on http://www.njk.no/~njk/kroeder/index_e.html and http://www.njk.no/~njk/index_e.html

[Binnie]

I've seen an old vitara with a coolant heater once before, i don't think the customer ever used it though.

Most cars do have diesel heaters from the factory, certainly all toyota's do, some eurotrash like my berlingo van however, won't have.

aftermarket diesel heaters are available and not bank breakingly expensive either.

a fuel heater is a MUST on vehicles using veg oil in winter, the cloud point of veg oil is a lot higher than diesel as far as i am aware.

A fuel heater is an essential mod for all those wishing to have a vehicle in cold weather post event, once the pumps run dry of course.

[Grumpy Grandpa]

Thanks yet again NR! Not that I have a diesel vehicle at the moment (or much of anything prep-wise yet ) but it's copied and filed for when (or if) it's ever needed.