[Karsten (OP)]

Last Friday we had close to -40C or F. Same at those temps really. Anyhow my car started fine, I went to work, only to be told that our school buses are having a hard time to continue running. Too cold they said and school was canceled. VERY annoying since I was there and now have to come back another day to make up that day. It seems other school districts had not issue with the cold temperatures. To me it seems our buses were not prepared.

I know you can mix an additive in the Diesel to keep it from gelling up. But how low can you go? What else could stop a Diesel bus from running at such low temperatures if it is already running. What is the lowest temperature for those additives to still work?

[Chemistry4me]

A disadvantage of diesel as a vehicle fuel in some climates, compared to gasoline or other petroleum derived fuels, is that its viscosity increases quickly as the fuel's temperature decreases, turning into a non-flowing gel at temperatures as high as -19 °C (-2.2 °F) or -15 °C (+5 °F), which can't be pumped by regular fuel pumps. Special low temperature diesel contains additives that keep it in a more liquid state at lower temperatures, yet starting a diesel engine in very cold weather still poses considerable difficulties.

http://en.wikipedia.org/wiki/Diesel

[Chemistry4me]

Anti-freeze 50/50 premix, diesel engine propylene glycol, school bus, 55 gallons/drum
Anti-freeze 50/50 premix, diesel engine ethylene glycol, school bus, 55 gallons/drum
Anti-freeze fully formulated, diesel engine ethylene glycol, school bus, 55 gallons/drum

http://www.phila.k12.pa.us/offices/procurement/awards/fy06/111605/M06-0030.pdf

[Karsten (OP)]

Anti-freeze 50/50 premix, diesel engine propylene glycol, school bus, 55 gallons/drum
Anti-freeze 50/50 premix, diesel engine ethylene glycol, school bus, 55 gallons/drum
Anti-freeze fully formulated, diesel engine ethylene glycol, school bus, 55 gallons/drum

http://www.phila.k12.pa.us/offices/procurement/awards/fy06/111605/M06-0030.pdf

So, it is more expensive? I don't get this one.

[Karsten (OP)]

The engines started OK. Many (or all) buses are plugged in at night and use electricity to heat the engine block. Now they are saying that their transmission froze up and that is why they had to cancel school even though they had already picked up many kids.

Is there no Diesel user here who also experiences extremely cold weather or who has a bottle of additive that may say what the lowest temperature is?

[Chemistry4me]

What is more expensive?

[DoctorBeaver]

I used to have a diesel Landrover and that was equipped with a cold start button. It would heat the engine for a few minutes before you started it.

[Karsten (OP)]

You linked a letter (requirement contract) that shows Diesel mixes at different ratios and prices. Why?

[Karsten (OP)]

I used to have a diesel Landrover and that was equipped with a cold start button. It would heat the engine for a few minutes before you started it.

As far as I remember from my time in driving school with the VW Golf Diesel this is to get your glow plug glowing. After a while the glow plug kept glowing by itself. Don't know if this is still necessary with modern Diesels. It surely will not warm the Diesel to a temperature that lets it flow again.

[DoctorBeaver]

I used to have a diesel Landrover and that was equipped with a cold start button. It would heat the engine for a few minutes before you started it.

As far as I remember from my time in driving school with the VW Golf Diesel this is to get your glow plug glowing. After a while the glow plug kept glowing by itself. Don't know if this is still necessary with modern Diesels. It surely will not warm the Diesel to a temperature that lets it flow again.

My Landrover was old.