Winter Fuel Mileage

[rtquig]

Since the weather has gotten pretty steady below 30F at night my fuel mileage has gone down. At the same time I have added Standyne to my fuel, which I don't think is hurting mileage, but not adding to it either. Can it be in the cold weather fuel is wasted because the engine is running colder than summer and not as efficient?

[BigLakeDMAX]

Diesel mileage often drops in the winter due to the use of blended fuel (the mix of #2 and #1 diesel to improve cold flow). My truck is down from just over 18 mpg to just under 17. A recent thread explains this.

http://forum.62-65-dieselpage.com/ubb/ultimatebb.php?ubb=get_topic&f=3&t=004588

I don't know if they blend fuel in Jersey but would guess they do if temps drop below freezing. You'd want to ask your fuel dealer.


Also, I read another thread recently where two members reported improved power with their cold weather covers on.

[ 12-23-2002: Message edited by: BigLakeDMAX ]</p>

[Kennedy]

My mileage has actually been pretty decent as of late. I've been between 16 and 17 (plus the 5% for tire size change) whereas I had been in the 15-16 range just bombing around. Our annual X-mas trip will log 1000+ miles so we will se how it does out on the road!

[AKDmax]

Last 2 tanks have been 11.68 and 12.82. Been below zero for a couple weeks so lots of idling.

[TooMuchMuscle]

I thought the same, low milage during the cold times, but I just got back from Flagstaff,AZ (nice place), temps in the 20's and I averaged 21 mpg. I usually only average 18 mpg in So Cal (same driving style). This is not scientific, but made me think twice. I love the DMAX!!!!

[ZFMax]

I check my mileage every tank.

All last winter I got mid 17's (combined city/hwy).

All last summer I got high 18's.

And as the weather cooled, it dropped back to mid 17's.

But, I recently removed the LT285/75R16's I've had on the truck for over a year, and went to LT265/75R16's. Only one tank so far on the new tires, but the mileage was 18.6!

Odometer correction factor with the 285's was 7.1%, based on a 300 mile non-stop across Kansas comparison of the odo to the mile markers. In other words, I was multiplying the miles by 1.071 before dividing by gallons.

Odometer correction factor with the 265's ... well, I haven't accurately measured it yet, so I'm using the value I calculated, which is 3.8%. That should be in the ballpark, but I need to check it carefully as well as run more tanks through before I declare for certain that 265's got me 1 mpg.

Subjectively, though, the 265's (BFG Commercial T/A A/S) helped acceleration vs. the 285's and are noticeably quiter. Also got rid of an annoying left pull.

[Jelisfc]

I just got back from hunting. Minnesota to Montana and back. 2100 miles pulling a 5'x 10' utility trailer. Empty out...two buffalo back (1500 lbs). Overall mileage 17.5 including 200 miles of offroad driving. They were dirt roads but calling them roads is a overstatement. smile.gif My worst tank was 14.0 doing 80 mph on I-90.

[Kennedy]

Got 17 first tank, 16.2 second tank (idle time and higher speeds) and 17 third tank on our Xmas trip.

[rtquig]

My mileage has gone down with the cold weather from 18-19 to 16.5-17, but I must say as JK noted in his post, I have been letting it idle a lot more than before. I like the truck to be nice and warm when I take the 2 year old to the babysitter in the morning.

[6X]

MIlwaukee to Minneapolis all highway milage 17.2

[Nels]

Osceola, IA to Manitowoc, WI last week. After filling up with winter blend at BP (Amoco) in Altoona, I drove the last 447 miles nonstop, averaging 65.7 mph and 21 mpg. Temps in the 20's. The trip down there the day before yielded 19 mpg with a couple of stops (about 800# in the box). Details in spreadsheet below.

[SoMnDMAX]

16.2 Last Monday using 60/40 #1/#2 fuel, from Sleepy Eye, MN to Marion, SD and back. 20 MPH head wind on the way out, no wind on the way back. Ambient temp around 15 degrees. 45 minutes idling @ 800 RPM when we arrived. Most of the trip was done at 75-85 MPH down I-90, and the rest at 60-65 on secondary roads.

Not too bad, IMHO.

[hdmax(mike)]

My last fill up was the worst running empty mileage I have got (on clean dry roads) sence the second tank full. And this was still 18.0 So I`m not complaining. My last truck wouldn`t see this kind of mileage even off a cliff. :eek: :eek:

[blue_lightning]

Are you guys using the grill covers? Just a thought, after reading one of the other posts about engine coming up to temperature,

Jelisfc writes:
"I have the grill cover on and noticed my mileage varies greatly from 17.5 to almost 22. If the temp gauge doesn't stay at 195 I get lower mileage. I thought it was the blended fuel but now you have me wondering. Tuesday I ran from Minneapolis to Des Moines and back, 540 miles and 45 degrees. Averaged 21.5 mpg. I'll have to keep an eye on my temp gauge."

I don't see any mention of the grill covers here or at what temp your engines are running at. Are you guys using the grill covers? If not, just curious how your mileage would compare if you do. Let us know.

[Jelisfc]

blue_lightning, I've had my grill cover on since November. During my trip last week I was concerned about expected temps in the 50's. Going across SD the temperature varied from 45 to 57. I never got out of the truck the whole tank. Cruise at 80, didn't feel any wind but it must have been strong becaue I got 14.0. I've noticed this truck handles high winds so well I can't tell how hard they're blowing and the engine has so much power the only thing that suffers is mileage. I need a boost gauge to be able to tell how hard it's working.

The quote is from a different post. I have watched my temp gauge closer since then and it normally runs on the highway at 195. It was in the 50's going out and in the mid 30's on the way back. Going to and from work (25 miles) it will fluctuate between 180 and 195. I'm just not working it hard enough empty.

[jbplock]

I have also noticed better mileage with the (upper) cover on. Temps here in upstate NY have been in the 20’s and 30’s. Without the cover the temp gauge would hover around 185 and mileage was dropping to between 16 and 17 MPG. With the cover on, temps are running about 195 (where it runs in warmer weather) and mileage is between 17.5 and 18.5 MPG. (I also use Standadyne Performance Formula) :cool:

[SoMnDMAX]

Blue_Lightning, The trip above was made with the upper half of the cover installed. My cover has been removed four times since early November, three times for washing and once for towing.

I have never installed the lower half of the cover.

[DmaxMaverick]

Has anyone considered blocking only the radiator? There is a space between the radiator and intercooler and can be accessed by removing the plastic cover over them. This would leave the condensor and intercooler open to fresh air. It seems to me that this would be much more efficient, only allowing the engine cooler to heat up, but leaving the intercooler to do what it does best. I would think that the result would be higher power levels and better MPG.

It doesn't get cold enough here for any length of time to offer a valid comparison, or I would. Would be interesting to find that it could be so simple.

[Jelisfc]

What about the fan? I remember the first Dodges wouldn't warm up at all in the winter. Horton came out with an electric fan clutch that replaced the factory one.

[SSWEBARRICK]

Picked my dmax up 12-6-02, just filled for first time last weekend and got 17.5. I use the truck for work. Drive on highway 30 miles each way to work, then off road (some 4x4) for 40 miles each day. Total of 60 miles highway, 40 miles off road each day.So far I love the the ride!!Looking forward to using my new dmax for a long time.

[FrozenAKJoe]

I'm also one of those anal diesel people who track every tank of fuel (my wife laughs at me, but who cares). It's been between 5-20F for the last week or so, and during that time I've run through a half tank of fuel. Mileage was 13.55 this afternoon. I'm running with the grill cover only.

This same time period last year had similar temps and I was getting roughly the same mileage (truck was brand new then, and it has 12,500 miles on it now). (So much for my new tonneau cover giving me better mileage. It looks good, however.)