RayMich
Well-Known Member
For several months, I've been complaining that my truck's fuel economy has been getting worse and worse. I have always service the truck myself and have been using synthetic oil since the truck had 4,300 miles. With the price of diesel fuel climbing on a daily basis, I've done just about everything I can think of, including driving like a timid grandmother trying to get better mileage, but this has been to no avail.
The only thing I had not changed was the air filter element. I've always checked the air filter gauge under the hood and it has NEVER moved from the green and visually inspecting the filter always showed it to be OK, so I figured it was good.
Last month I was servicing the truck, getting ready for a 4,700+ miles trip to the Florida Keys and I was dreading the thought of burning all that expensive fuel. Again, a look at the air filter gauge and visual inspection revealed that the air filter element appeared to be OK. But I though, what the hell, the truck had 29,000 miles on it and maybe a new air filter element would help. I went to the local part store, but they did not have the OEM filter, so I decided to bite the bullet and called the local Chevy dealer. Lucky for me, he had ONE OEM filter left, but the bad news was that it would cost me $63.76 with tax for the AC Delco element.
I decided that after 29,000 miles the truck could use a little "treat" so I bought the new AC Delco air filter and installed it.
Low and behold, my mileage went up by almost 3 MPG, just by installing the new OEM air filter element.
I have kept meticulous record of every single gallon of diesel fuel that has gone into my truck. After I return from my trip I calculated my fuel economy for the whole trip as well as for the portion I ran with the A/C OFF.
The round trip was 4,710 miles from Michigan to the Florida Keys, Key West, then to Sarasota, then Shreveport LA, to Atlanta GA and finally back to Michigan. I ran with the cruise control ON at 70 MPH whenever possible. there were a few instance when I pushed it up to around 80 while passing. This trip included driving with the A/C on while in the hot and humid Florida and Louisiana climates as well as some towing a 19 ft fishing boat, motor and trailer while down in the Keys.
My truck was 100% pure stock during this trip and I hand calculated fuel economy after every fill-up. My worst calculated fuel economy for one tank was 17.83 mpg, which included some city driving while visiting family in Florida, and the best was 20.24 mpg while driving from Shreveport to Atlanta.
Here are the results:
Total Miles Driven: 4,710 miles (Round Trip)
Total Fuel Burned: 252.547 gallons
Hand Calc'd Economy: 18.65 MPG
I then decided to calculate my fuel economy during the time that I did not need to run the A/C and here is what I got:
No A/C Miles Driven: 1,356.6 miles (A/C OFF)
Total Fuel Burned: 69.050 gallons
Hand Calc'd Economy: 19.65 MPG
Not bad for a pure stock truck while still running at 70+ MPH.
The only thing I had not changed was the air filter element. I've always checked the air filter gauge under the hood and it has NEVER moved from the green and visually inspecting the filter always showed it to be OK, so I figured it was good.
Last month I was servicing the truck, getting ready for a 4,700+ miles trip to the Florida Keys and I was dreading the thought of burning all that expensive fuel. Again, a look at the air filter gauge and visual inspection revealed that the air filter element appeared to be OK. But I though, what the hell, the truck had 29,000 miles on it and maybe a new air filter element would help. I went to the local part store, but they did not have the OEM filter, so I decided to bite the bullet and called the local Chevy dealer. Lucky for me, he had ONE OEM filter left, but the bad news was that it would cost me $63.76 with tax for the AC Delco element.
I decided that after 29,000 miles the truck could use a little "treat" so I bought the new AC Delco air filter and installed it.
Low and behold, my mileage went up by almost 3 MPG, just by installing the new OEM air filter element.
I have kept meticulous record of every single gallon of diesel fuel that has gone into my truck. After I return from my trip I calculated my fuel economy for the whole trip as well as for the portion I ran with the A/C OFF.
The round trip was 4,710 miles from Michigan to the Florida Keys, Key West, then to Sarasota, then Shreveport LA, to Atlanta GA and finally back to Michigan. I ran with the cruise control ON at 70 MPH whenever possible. there were a few instance when I pushed it up to around 80 while passing. This trip included driving with the A/C on while in the hot and humid Florida and Louisiana climates as well as some towing a 19 ft fishing boat, motor and trailer while down in the Keys.
My truck was 100% pure stock during this trip and I hand calculated fuel economy after every fill-up. My worst calculated fuel economy for one tank was 17.83 mpg, which included some city driving while visiting family in Florida, and the best was 20.24 mpg while driving from Shreveport to Atlanta.
Here are the results:
Total Miles Driven: 4,710 miles (Round Trip)
Total Fuel Burned: 252.547 gallons
Hand Calc'd Economy: 18.65 MPG
I then decided to calculate my fuel economy during the time that I did not need to run the A/C and here is what I got:
No A/C Miles Driven: 1,356.6 miles (A/C OFF)
Total Fuel Burned: 69.050 gallons
Hand Calc'd Economy: 19.65 MPG
Not bad for a pure stock truck while still running at 70+ MPH.
Conclusions:
* The Air Cleaner Gauge is totally useless.
* Change the air filter at 15,000 mile intervals even if it still looks good.
Even though I paid the full retail price of $63.76 for the new air filter, I saved more than three times that much in fuel cost during my trip.* The Air Cleaner Gauge is totally useless.
* Change the air filter at 15,000 mile intervals even if it still looks good.
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