Originally Posted By: yee
I am considering a diesel genset but failures in CT are frequently due to down wires (read...snow). Given the difficulties in starting a diesel in the cold without power, wouldn't it be difficult to run a diesel genset. This particular storm was in relatively WARM weather.


Being a diesel mechanic, the first big problem I notice people have with starting diesel engines in the cold is that most people fail to use the proper oil. They try to use the standard 15w40, which is only good down to about 20*F/-7*C. The old fix for that used to be switching to 10w-30 in winter.

Nowadays, we have synthetic 5w40 and even 0w40. These are good down to about -20*F and beyond. We buy CJ-4 rated 5w-40 for all our diesel equipment and it's started perfectly fine for us down to -27*F (which is the coldest we've ever had our trucks, and the block heaters weren't even plugged in!).

The second problem people have is that they fill up their generator or equipment with fuel in the summer, and then forget about it until winter. Well, winter diesel is formulated differently from summer diesel to have a lower gelling point. If you don't use the right fuel it can start to gel once the temp gets below freezing. The old fix was adding some #1 diesel (kerosene), up to about a 50/50 mix.

Nowadays we have diesel anti-gel additives (also called diesel winter conditioner). This stuff can keep a diesel engine starting down to about -40*F. We use Power Service Diesel Fuel Supplement (comes in white bottle).

The third problem comes down to batteries. Diesels require a higher torque starter than a typical gas engine and therefore require more amps at startup. If you've got an electric starter you want to make sure you've got batteries in good condition that are well charged. We use smart trickle chargers to help maintain batteries on seldom used equipment (specifically Deltran Battery Tenders).

If you use the right oil, use a good anti-gel, and perform basic battery maintenance, you shouldn't have any problems starting a diesel genset in winter.


[On a side note, just like you keep spare spark plugs on hand for a gas engine, I recommend keeping spare fuel filters on hand for a diesel. I like to change them when I change the oil, about every 200-400 hours. On gas generators I'll change the plugs and oil every ~100 hours.]