Jump to content

2500HD gas mileage

BrianB65

By BrianB65
in 6.6L Gas V8 (L8T)

 Share

Recommended Posts

Ray Pickle Enthusiast

Ray Pickle

Posted
Posted
On 7/13/2022 at 5:57 PM, Flatus said:

I pulled a 5300 lb travel trailer about 600 miles the last few days. Only 8.5 mpg's for me. I never ran over 65 mph.

Kinda disappointing.

Was that stop and go in town for a significant % of the tow? Possibly high headwinds or front quartering winds? That is low mpg for what you are pulling if your speeds are 65 or less. I average that pulling a 12k 13.5 ft tall fiver in the west and a little over 9 in the midwest. I acknowlege a fiver has better aerodynamics than a travel trailer but your shorter length, less height, and weight should more than make up for that.

  • Replies 57
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

Another JR
Another JR

I’m not saying anything about its accuracy, but FYI the trip pages show avg mileage over the trip from the last trip reset. 

Cheekster96
Cheekster96

Put in just over 24 gallons of Shell 87 tonight...had just over 1/4 tank left and hand calculation revealed 15.69 mpg.  I almost had a heart attack when I paid $125!!!   DIC trip A gave me 1

Marty303
Marty303

9.5 towing 10,000 lb 5th wheel from South Texas to Colorado with tail wind and driving 65 mph. Colorado to South Texas, 6.9 with strong head wind. Sometimes driving as slow as 60 mph.  

Posted Images

Flatus Enthusiast

Flatus

Posted
Posted
8 hours ago, Ray Pickle said:

Was that stop and go in town for a significant % of the tow? Possibly high headwinds or front quartering winds? That is low mpg for what you are pulling if your speeds are 65 or less. I average that pulling a 12k 13.5 ft tall fiver in the west and a little over 9 in the midwest. I acknowlege a fiver has better aerodynamics than a travel trailer but your shorter length, less height, and weight should more than make up for that.

90-95% highway. Light winds. Coastal Mississippi to Northern Mississippi and back. Rolling hills but definitely not mountainous. 

sheath Enthusiast

sheath

Posted
Posted
On 7/15/2022 at 6:52 PM, Flatus said:

90-95% highway. Light winds. Coastal Mississippi to Northern Mississippi and back. Rolling hills but definitely not mountainous. 

I would have expected better mileage as well, especially since your truck is 2WD.  Like in the 9+mpg range.  

Wonder if you got a bad tank of gas?   Are you normally getting in the 14+mpg when not towing?

Flatus Enthusiast

Flatus

Posted
Posted
3 hours ago, sheath said:

I would have expected better mileage as well, especially since your truck is 2WD.  Like in the 9+mpg range.  

Wonder if you got a bad tank of gas?   Are you normally getting in the 14+mpg when not towing?

I get 12-13 mpg in my everyday driving. My normal daily drives are a lot of 15mph- 45mph roads with plenty of stop signs and red lights though. I have not been on any road trips without towing something. About a month ago I drove to a lake in Alabama while towing a 16ft skiff with tiller motor. Truck had 3 people and bed was loaded with coolers and few other things.  I got 15 mpg on that trip. I always hand calculate my mpg because computer is always optimistic.

sheath Enthusiast

sheath

Posted
Posted
23 hours ago, Flatus said:

I get 12-13 mpg in my everyday driving. My normal daily drives are a lot of 15mph- 45mph roads with plenty of stop signs and red lights though. I have not been on any road trips without towing something. About a month ago I drove to a lake in Alabama while towing a 16ft skiff with tiller motor. Truck had 3 people and bed was loaded with coolers and few other things.  I got 15 mpg on that trip. I always hand calculate my mpg because computer is always optimistic.

Yeah, it sounds like normally your truck does pretty good.  Hopefully the tow down south was just a bad tank of gas, that doesn't repeat. :cheers:

Flatus Enthusiast

Flatus

Posted
Posted
55 minutes ago, sheath said:

Yeah, it sounds like normally your truck does pretty good.  Hopefully the tow down south was just a bad tank of gas, that doesn't repeat. :cheers:

That trip was 2 different tanks of gas from 2 different Chevron gas stations. Same results on both.

Flatus Enthusiast

Flatus

Posted
Posted

^ The 8.5 mpg trip pulling the camper was 2 different tanks of gas from 2 different Chevrons is what I mean.

sheath Enthusiast

sheath

Posted
Posted
20 hours ago, Flatus said:

^ The 8.5 mpg trip pulling the camper was 2 different tanks of gas from 2 different Chevrons is what I mean.

Pretty strange indeed. i have no idea why that happened to you.  With the crazy price of gas I sure hope it doesn't happen again.

Flatus Enthusiast

Flatus

Posted
Posted

I will be doing the same trip on Labor Day weekend for college football game so will see how it goes on that trip.

  • Like 1
Ray Pickle Enthusiast

Ray Pickle

Posted
Posted

Is your truck pulling in 5th and occassionaly in 6th gear on flats to 2% grades? If not something isn't right. Do you lock out top 2 gears and pull in 4th to keep revs up? If so that would account for poor mpg. Iam at a loss otherwise for poor towi ng mpg. I can maintain speed on level ground up to 2% grades in most instances in wither 6th or 5th gear. Rarely do I downshift to 4th and rev to 3k range unless terrain is more hilly or headwinds. Check trailer brake adjustment, tire pressures on both?

sheath Enthusiast

sheath

Posted
Posted

Remember the old days when trucks got 10 mpg uphill, downhill, towing 10 bazillion pounds, or free falling off a cliff?  lol 

I've noticed this truck has fuel mileage that ranges all over the place.  The most consistent fuel mileage is when towing the 14,600lbs 5th wheel.  It will either be approximately 8.5 mpg on the flats, or approximately 7.5mpg through the mountains.   Unloaded in town and on the interstates with 75-80mph speed limits drops mileage into the high 13 to mid 14 range.  Long back road trips will be high 15 to low 17mpg.

 

I've not had a truck before with fuel mileage this variable.  This is also the first HD gas engine truck I've owned that would run through a full tank at over 15mpg.  Since it runs on 87 Octane that is a double bonus.

 

All the driving represented in the below spreadsheet is at a conservative acceleration rate with speeds at or below the posted limit or basic speed law (lower of the two).  Cruise control use is maximized (I'm too lazy to push a gas pedal when I can push buttons on a steering wheel... lol).  The rows below with mpg in the 9-13 range is a combination of towing and unloaded.

 

One other note: mileage is hand calculated.  But I don't top off, and this is over many different fuel pumps.  So I'd guess there could be up to a 0.3-ish mpg variance due to this.

 

Date Mileage Fuel / Maintenance 20   Mileage
02/28/22 371 Fuel     14.19
03/01/22 821 Fuel     15.60
03/18/22 1126 Fuel     12.75
03/31/22 1115 Month end     14.18
04/02/22 1517 Fuel     13.02
04/03/22 1738 Fuel     7.42
04/03/22 1974 Fuel Partial fill 16.952 gls   N/A
04/03/22 2053 Fuel Final fill 19.882 gls   8.55
04/09/22 2398 Fuel Partial fill 17.2446   N/A
04/11/22 2488 Fuel Final fill 15.960   13.10
04/26/22 2767 Fuel Partial fill 23.152   N/A
04/27/22 2966 Fuel Final Fill 16.466   12.07
04/28/22 3221 Fuel     15.47
  2095 Month end     11.60
05/06/22 3509 Fuel Partial fill 23.325gls   N/A
05/08/22 3551 Fuel Final fill 9.831gls   9.96
05/09/22 3847 Fuel Partial fill 30.308gls   N/A
05/10/22 4018 Fuel Final fill 20.061gls   9.27
05/10/22 4224 Fuel     8.15
05/15/22 4632 Fuel Partial fill 15.682 gls   N/A
05/17/22 4785 Fuel Final Fill 24.261 gls   14.05
05/22/22 5154 Fuel Partial Fill 15.309gls   N/A
05/22/22 5154 Fuel Final Fill 8.132   15.74
05/22/22 5154 Engine Oil Top off engine oil w/5-30   N/A
05/23/22 5284 Fuel     7.71
05/24/22 5490 Fuel     8.67
05/30/22 5901 Fuel     15.91
  2680 Month End     11.18
06/01/22 6073 Fuel     14.49
06/01/22 6261 Fuel     9.04
06/02/22 6517 Fuel Partial Fill 18.754 Gal   N/A
06/03/22 6553 Fuel Final fill 14.659 gal   8.74
06/07/22 7027 Fuel 29.054 gals   16.31
06/08/22 7368 Service First Oil Change   N/A
06/09/22 7416 Fuel Partial fill 18.004 gals   N/A
06/12/22 7516 Fuel Final Fill 11.960   16.32
06/18/22 7966 Fuel     16.43
06/20/22 8356 Fuel     13.90
06/23/22 8422 Service Tire Rotation    
06/28/22 8729 Fuel     11.91
06/29/22 9145 Fuel     17.28
  3244 Month End     11.31
07/03/22 9586 Fuel     16.52
07/11/22 9860 Fuel     15.03
07/11/22 10243 Fuel     17.09
07/11/22 10599 Fuel Partial Fill 15.499 gals   NA
07/13/22 10627 Fuel Final Fill 7.489 gals   16.70
07/15/22 10803 Fuel     15.84
07/16/22 11193 Fuel     17.21
07/16/22 11693 Fuel Partial Fill 28.852 gals   NA
07/17/22 11889 Fuel Partial Fill 16.669 gals   NA
07/17/22 12170 Fuel Partial Filll 5.099   NA
07/18/22 12410 Fuel Final Fill 31.577 gals   14.81
07/19/22 12731 Fuel     14.34
07/21/22 13111 Fuel     15.98

 

  • Like 1
Another JR Senior Enthusiast

Another JR

Posted
Posted

Maybe the OP could post a picture of the truck and trailer combination. Maybe he has a very high aerodynamic drag configuration - like a bumper pull trailer with large frontal area and an open truck bed.  

Flatus Enthusiast

Flatus

Posted
Posted
3 hours ago, Ray Pickle said:

Is your truck pulling in 5th and occassionaly in 6th gear on flats to 2% grades? If not something isn't right. Do you lock out top 2 gears and pull in 4th to keep revs up? If so that would account for poor mpg. Iam at a loss otherwise for poor towi ng mpg. I can maintain speed on level ground up to 2% grades in most instances in wither 6th or 5th gear. Rarely do I downshift to 4th and rev to 3k range unless terrain is more hilly or headwinds. Check trailer brake adjustment, tire pressures on both?

My truck pulls anywhere from 4-6 gears. It will hit the 3000-3200 rpm range occasionally. I do not lock out any of the gears. I do put it in Tow/Haul mode every time I tow the camper though. Maybe I should try a tow without doing that. My trailer only weighs about 5200-5400 lbs loaded which technically is below the threshold that I should be using Tow/Haul according to owners manual. I keep up with my tire pressures regularly, including the camper. I actually use a TST pressure/temp monitor for camper tires. As far as grades go, I have no idea what percentage grades/hills I go up and down on. 

Ray Pickle Enthusiast

Ray Pickle

Posted
Posted
On 7/25/2022 at 6:59 PM, Flatus said:

My truck pulls anywhere from 4-6 gears. It will hit the 3000-3200 rpm range occasionally. I do not lock out any of the gears. I do put it in Tow/Haul mode every time I tow the camper though. Maybe I should try a tow without doing that. My trailer only weighs about 5200-5400 lbs loaded which technically is below the threshold that I should be using Tow/Haul according to owners manual. I keep up with my tire pressures regularly, including the camper. I actually use a TST pressure/temp monitor for camper tires. As far as grades go, I have no idea what percentage grades/hills I go up and down on. 

I agree to consider non- tow haul at your weight the truck will pull in 6th gear far more often which may improve your mpg.  I would be curious of your results, please let us know if you try it. I'm such a frugal bastard I will turn tow-haul off whenever conditions allow to maximize mpg with a 12k fiver! Any sustained downhill grades or hills that it can safely be executed, or on level ground- slight inclines with a tailwind!

  • Like 2

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,760
    Total Members
    8,960
    Most Online
    MASONV88888888
    Newest Member
    MASONV88888888
    Joined

  • Who's Online   2 Members, 0 Anonymous, 1,343 Guests (See full list)

  • Latest Articles

  • Posts

    • MASONV88888888
      Another 6.2L engine failure!

      By MASONV88888888 · Posted

      My 2025 Silverado 1500 had to receive a brand-new engine (long block) under warranty last month at only around 16,500 miles. Before the replacement, the truck repeatedly displayed "Engine Oil Level Low" warnings, even though the Oil Life Monitor still showed around 50% remaining after about 6,000 miles since my last oil change. After seeing the warning several times, I checked the dipstick with the engine cold, and the oil level was completely normal. The next day, the message escalated to "Add Engine Oil." At first, I assumed it was just a faulty oil level sensor, so I brought the truck to the dealership. After inspecting the engine, they found internal cylinder wall scoring and ultimately replaced the entire long block under warranty. Before this happened, I was planning to install a 4-inch lift and suspension upgrade on my truck. After needing a new engine at just 16,500 miles, I honestly don't see the point anymore. I also contacted GM to ask whether my vehicle qualified for a buyback, but I was informed that it does not at this time. Anyway, this experience has left me with serious concerns about the long-term reliability of this engine. I sincerely hope NHTSA expands the current investigation or recall to include 2025 model and performs a thorough inspection of affected vehicles. My biggest concern is that these engines may fail shortly after the powertrain warranty expires. If GM truly stands behind this engine, then at the very least, please consider extending the powertrain warranty to 10 years for affected owners. That would go a long way toward restoring customer confidence.
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      Without exception but then I'm the odd duck, right? I know what goes into that test, how it is calculated and thus how to beat it. But EPA values are often not beaten by the general public and the government has in past years adjusted the means and methods to come to those values to more closely approximate "Joe Average".    The only real trick to beating that EPA average is don't drive like "Joe Average".    It's the same method you used to profit from "Economic Migration" and in doing so beat the 'stats'. But you, like me, are not "Joe Average".     The thing you don't seem to grasp is this "Purchasing Power Index" isn't forward looking. It doesn't predict what it going to be but looks backward and states what it was. They are not telling us what the THINK, they are telling us what they MEASURED. Example:    Wife says "I'm going to lose 40 pounds by Christmas". May she does, maybe she doesn't but the doctors office who weighed her when she made that statement and again at Christmas only REPORTS what the RESULT was. You and I can banter about what was possible and what aunt Tilly did till the cows come home but the result is the result. Arguing otherwise is.....irrational. That's all I'm saying. This isn't about:      What you are calling a 'Statistic' is a RESULT not a CALCUATION and as a result the RULE. Like gravity as a rule, it can not be broken. 
    • MASONV88888888
      Rattle in the rear!

      By MASONV88888888 · Posted

      Just wanted to say thank you for posting this. Years later, your thread is still helping Silverado owners.   I bought my 2025 Silverado 1500 in January 2025, and I've had what feels like the exact same rattle since day one. After reading your findings, I believe my truck has the same issue with the cable carrier contacting the rear sliding window. To be honest, I had pretty much given up on pursuing the issue. It wasn't until I recently drove another brand's pickup that I realized just how quiet their cabin was—and how noisy mine has been all along. On my truck, the rattle happens on almost any paved road, gets even worse on rougher pavement, and I can even hear it during braking and acceleration.   I actually referenced your thread when submitting my case to GM, hoping they'll recognize this as a recurring issue instead of treating it as an isolated incident. The reason I reached out to GM first is because my dealership told me they would need to keep the truck for at least two days just to diagnose the problem. I was concerned that even after two days, they still might not be able to identify the source of the rattle before giving the truck back to me. I had also asked a few dealerships about this issue during previous service visits, but none of them seemed to know what was causing it or had a solution. That's why I decided to contact GM directly first, hoping they might already have an official repair procedure or guidance for this issue.   I also hope GM eventually comes up with an official fix for this problem. I have a feeling there are many Silverado owners experiencing the same rattle, but most either choose to live with it or simply don't know what the cause is.   Really appreciate you taking the time to document your diagnosis. Your post is still making a difference years later.
    • Buckwild27
      Gas Prices

      By Buckwild27 · Posted

      I have 2 choices. 
    • Grumpy Bear
      Gas Prices

      By Grumpy Bear · Posted

      Do you have access to BP fuels? Some stations have Silver 91 E-0 priced the same as their 93 E-10.  There is a local Marathon with 90 alky free for $6 a gallon but I go down the road to BP for $5-ish. They also have a 100 E-0 but that stuff is $10 a pop. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...