At what temperature do you need to start worrying about diesel fuel gelling? Next week we will be traveling to Bryce Canyon for a week or so, then on down to Arizona for the winter. We could see temps dip down in the low 20's at night. Is that a problem? This is our first Diesel, and I'm not sure what to expect.

Should be ok. If you're worried, add some stanadyne or other big name anti-gel.

Low 20s should not be an issue at all. And in cold weather, if you buy fresh local fuel, it should be "winterized" to reduce the wax point temperature sufficiently to avoid problems in all but the coldest weather.

Slightly off-topic but does ULSD have a summer and winter blend? I was told by a fuel delivery person that with USLD there is no need to change the blend for cold temp... Does anyone have info on this?

I have 135 gal on board (40, and 95 gal tanks) so I don't always have fuel from the local area. I just filled up with #2.

Thanks for the information

Mike

I hadn't heard that about ULSD, but I wonder if it has to due with all the additives they put in to get the lubricity back. Also possible that they've taken out most of the high cloud-point compounds. I need to do some reading on that...

As to the question at hand, with the fuel injection system as it is on the Duramax (heated filter, ECU heating the fuel, etc.), you're fine with even summer diesel down to the 20's.

I would add an anti gel additve to be safe. Add some Power Service (make sure it's the one for cold weather) and you'll sleep a little better. If you have untreated diesel it can start to form crystals at that temp which will plug your filter first and you will have poor fule delivery, stalls and no starts.

ULSD will still have to be blended for winter performance. I don't like #1 or kerosene blends. Like to find #2 with a good anti gel additive. Loose to many BTU's on the blends and the cost is usually more for the #1 and kerosene blends.