winter/arctic diesel

[lmp]

Could anyone, please, explain me a little bit more detailed about diesel in winter.

At first everything looks simple - I drive in to fuel station, fill up fuel market with -32°C and feel safe as it is highly unlikely the temp will drop bellow -24 ... -25°C, I  have quite a good margin. But when I take closer look into fuel specs, for example local Neste home page sates that A2 class fuel has Cloud Point (whatever that means) at -22°C and CFPP (even more - whatever that means) is -32°C 

Of course I have read about those two parameters  but I still couldn't get it and am interested in real world situation: I'm safe till -22°C or till -32°C? For example if at morning I see -25°C it is safe to start car and drive to ... wherever I need?

As car is almost new, I don't expect any other issues than fuel and fuel system.

What about DSG gearbox? Perhaps as everything - while it's cold "soft" driving is highly recommended.

Thanks! Cheers! 

[brettikivi]

two points: 

 - I assume you have a block heater 

 - I assume you have fully filled with the winter quality?

 

the issue is the solidification of the wax in the fuel rather than anything else. This is where the block heater comes in and then the fuel return line; if you have a warm block, then the fuel which returns is also nicely warm. This should be enough to help any problems.

But still, keeping the filter clear is a good idea. And I don't know how much you've experienced -30 or so, but oil is very thick at that point and on a manual you'll really feel it. No suspension travel to speak of, squeaks, crappy bass, and difficult gearchanges are the order of the day. Drive gently, full stop, and don't be surprised if you don't hit operating temperature. Your tyres will also drop pressure quite a bit depending on just how cold they are, but TPMS should not have a problem with it as it should be consistent across all tyres. 

Plug in the block heater / DEFA, and if you don't have one, let things warm through for a few seconds before moving off (and a short excursion to 1500rpm is probably not a bad idea to move oil around before demands are put on the car). 

A few years ago I had to take my A2 for Katsastus - inspection - and it was -32. I'd prewarmed for 2 hours, then drove for a good 10kms via the motorway to make sure the cats were up to temp before going to the station. While I was there, passing emissions, the next lane had an Astra which was being revved mercilessly to get it warm enough to pass the emissions test... cold cats and no hot gases is a bad combination for emissions.

 

 - Bret

 

[Petunet]

Shouldn't be a problem, I had -34°C diesel in the tank on my Seat Cordoba TDI and the car outside temperature meter showed -35°C.

2 hours of warming with a block heater before start and I drove a 100km journey without any engine/diesel problems.

 

Door locks froze up during the drive so I couldn't get out of the car except through the trunk but ½ hour warming sorted out that too...

 

Gearbox uses small gears for 10-15km before it starts to warm up, then it's ok.

 

On a very cold morning at -38°C my 4x4 Subaru locked the wheels just by pressing the clutch without touching the brake pedal, the oil in the gearbox was so cold that it was almost solid.

 

[chimaera]

Cloud point is the temperature at which some fuel components will start solidifying: the fuel will turn cloudy as this happens. Cold filter plugging point is the temperature where enough of the fuel has solidified to the point where it will block the fuel filter and prevent fuel reaching the engine.