I've seen a drop of almost two mpg since the weather turned cold. This is over several tanks so I have a good sample set (always hand calculated).

Since this is my first diesel, I don't know if this is normal?

Can the cold weather cause this much of a drop?

 

Hum.
I thought for sure I'd see a drop in MPG with the "winterized fuel", but no such thing has happened. Still varies between 19.6 - 19.8 MPG. (overhead readings)

 

jonesm8,

With winter blended fuel many see a loss of 1-3 mpg as it is mixed with diesel #1 and #1 has lower BTU's then #2 diesel. Also the new ULSD has given many a loss of 1-2 mpg. So in plain words yes it is normla to see lower mgg in the winter time.

kutch,

FYI, overhead readings are not always close to what you get if you were to hand caluate your fuel mpg. I've heard of many that are off by up to 5 mpg.

 

Thanks DBLR,

That makes me feel a bit better. I was having some rough idle and white smoke..thought I might have had an injector problem.

 

Overhead reads between 19.5-19.8.
Hand calcs show 19.2.
Not off too much...thankfully.

Kutch

 

I've been using the new usld now for several weeks, and I haven't seen any drop in mileage,and I'm in for fuel several times in a week. mainly use BP,and flying J.

 

I've lost 2 to 3 mpg since it's gotten cold. I'll let it idle for 5 minutes before leaving, takes about 12 minutes to get to work, and the truck isn't up to temp yet (this is with the cold winter front with only one flap open). If my truck isn't reading 190 degree's my MPG sucks no question about it.

 

You guys think that your overhead is really far off.....

Well, mine is always 7-8 mpgs off

when i average 19 it says i'm getting 26

 

I switched to Rotella 5-40 about Thanksgiving (about the same time they switch to winter blend) and have noticed about .5 mpg increase in fuel economy. Can't wait til summer.

 

Normal for me as well on winter fuel. I used to lose about 1-2 mpg with my 2001 Powerstroke, and the same now. Winter fuel + ULSD has knocked my normal around-town mileage from about 12.5 avg (remember, I have a dually with 4:10s) to 10.98 this last tank.

And no, I'm not blowing excessive white nor black smoke, and the engine has power and purrs like a kitten. I am due for a fuel filter change soon, but the cold weather has always played a role in my mileage.

 

Ditto on the cold weather hurting MPG... 1-2 MPG is the norm for me. Short trips under 30 miles really hurt you... 10-16 miles to bring my truck up to 195. Not sure yet on REAL cold as it has been so warm here in the NE. Getting to 195 is not the all of it. You need to get all the coolant up to temp too.

I get significant dips at first till temps normalize. 20+ miles.

So it's like you have your "choke" on for the first 10-20 miles and get worse MPG. In the cold on long trips 60 to 150 miles It's not as bad.

Now when it's below zero... EVERYTHING is stiff and rolling resistance is very high. 5-10 below from a cold start really takes a lot of fuel to loosen up/warm up all that stuff. a 5-6 MPG loss is not unheard of for me then. Now add the plow, 4x4, and the forward reverse dance... I can hit 10 MPG on a tank. That's down almost 50% from a long trip on a warm day.

Even with all that it's better than a gasser.

 

I haven't seen any cold weather up here in MD yet this year. Not sure how much of a hit you would see in AL.

As far as winter mileage goes, I see that I had lower mileage readings in Jan-Feb 03 and 04, but nothing really in 05 or 06.

 

Have you invested in a winter front for your truck, it sure does help warm it up faster then with out it. I can plug mine in for only 2.5-3 hrs and with the winter front I have 70 plus degree heat from the vents in 3 blocks, 100 degree heat in about 1 mile and I'm at full operating temp of 195 in about 10 miles. Also back in Oct I switched to 5w40 synthetic oil and that sure has helped out with cold start up noise.

 

I have the winter front and plug mine in as well. Still doesn't warm up for about 7 to 10 miles. It has been below 30 here for highs tho and is expected to be a high of 12 this weekend

 

7-10 miles for full operating temp is good. Now if you were to leave it plugged in longer it will warm up the block more. My 2-3 hr plug in time is based on over night lows in the mid to upper teens. Have you closed off any of the flaps on your front? at temps in the lower teens or colder 1-2 flaps open is all you need. When it was at -4 below I only has one flap open and had no over heat issues. Anyway with it plugged in for 4 or more hrs at temps down to zero with you having a winter front, I think you should have over 100 degree heat from the vents in under 2 miles. BTW, you have to remember that it takes time to heat up 7 gallons of coolant in the cooling system and a iron block.