Fuel Tracking – 2016 – End of Year

Three months into winter up here in the North and the MPG takes a dive!

All 2016 data is based on a highway commute averaging 2,468 ± 247 miles per month.  This was done over the same stretch of highway, in the same 2004 V6 Impala LS, with the same driver, at about the same times each day.  My commute to work is about an hour each direction.  In Total for this year: I used 1,009 gallons of gas, drove 29,624 miles, and spent $2,171 on fuel.  Yea, this car has about 289,000 miles.

In November the Walmart Goodyear Viva 2 tires were replaced with new Douglas All Season Tires… a much smoother ride.  The rear bearings were also replaced in November (much quieter now), the A/C condenser in June, and oil every month (except for March and October), rear brakes were completely rebuilt (including emergency cables) in April.  Tire pressure is 30 PSI… that is critical for a good efficient ride.


Average miles per gallon (MPG) continues it sharp decline into the winter months. The gas prices are mostly stable, with a slight holiday inspired uptick.


Average MPG generally follows the average temperature for the month… with some deviation at the upper ends. Oct, Nov, Dec generally fall on the line, as expected.

Chart Gas Stats Chart updated for july

Fuel Tracking – June 2016 – Chart

June Gasoline Use and Statistics:

MPG and Gas Price as of June 2016

Since MPG is usually related to operating temperatures, with colder temperatures being less efficient for automobiles. We can see a nearly linear correlation between the average daily temperature and the car’s fuel efficiency (MPG). From this relation we see the MPG is 25.128 plus the temperature times 0.087.  Next month, the temperatures may increase. We can start see a slight tapering off, at temperatures above 55F. This might indicate a plateau, where temperature no longer has a major effect… More data is needed…

MPG vs Temperatuer Correlation as of June 2016

Table Data:

Distance driven (miles)2,764
Fuel used (gallons)89.739
Efficiency (MPG)30.80 ± 1.5
Fuel cost ($)$221.89
Average fuel cost per gallon ($/gal)$2.47
Carbon dioxide released (LBS)*1,586
CO2 efficiency (LBS/mile)0.574

*Assumes 10% ethanol for 17.68 lbs-CO2/gallon.

Diagram showing where the radiator and condenser are located

Car Air Conditioner Condenser Replacement – 2004 Impala

Some time before last summer, that is way back in 2014 the air conditioner on my 2004 Impala went out. And, I put in a can of dye to see where the leak was at. No luck, I could hear the leak, but I didn’t see anything… After toasting for most of last summer and roasting on a 4 hour 92F drive to my sisters house, I finally purchased a new condenser.  Actually, I wasn’t completely sure that I had found the leak.  You can hear and see the gas coming out, but I wasn’t able to figure out where… The hoses all looked ok, the compressor, filter, dryer, and such all seemed ok. So, I was assuming the leak was on the back side of the condenser.

In your car, your air conditioner contains 6 major parts. There is a compressor (usually belt driven, unless you have a Prius) that squeezes the gas (normally Freon 134a) into the condenser. The condenser is up front before the radiator and is air cooled with fans and by driving. It is here that the higher pressure freon vapor is being forced into a smaller space and tries to give up extra energy as heat as it becomes a liquid. Basically, you are making the gas into a liquid, the free energy that kept the molecules flying about needs to go somewhere – which is why iti air cooled. Then, the liquid goes through a filter-dryer to screen out solids and catch any impurities. Then it is pushed through a small restriction to make a sudden pressure drop into the inlet of the evaporator. This makes an adiabatic expansion, where the liquid is being forced into a vapor state with out any heat being applied. The compressor is sucking on the evaporator to make the pressure lower. The lower pressure causes the liquid to try and go into the gas state (forced boiling). This needs energy to keep the molecules moving about as a vapor, and so, the evaporator gets cold. A fan then blows air over your evaporator to cool your car, and give heat to the cold freon.  You get air conditioning!


To replace the condenser… it is simple.  I am assuming you have a good leak, and all the freon is out of your car.  If it is not, you need to have a technician reclaim it for you.  Technically, R143a is used as a canned dusters… so, releasing it is not that bad.  Still, try to save the ozone layer.

New Condenser: Almost OEM style…


New Seal Kit and Plastic Clamp

A/C Seals KitAC Plastic Clip Clamp

Step 1: Locate the parts. The condenser is typically in the front of the car, in front of the radiator. As shown in the photo, they are actually under the front frame of the car. We will need to remove all the parts that are in the way.

Step 2: Start by removing the engine mounting supports. These are held in with 4 bolts on the front and a single longer bolt on the engine. You might be able to swing them up on top of the engine and out of the way.

Step 3: Remove the two diagonal support rods on the right and left. These have two bolts at the front and one at the rear. These are for crash stability to deflect force outward to the sides of the car.Diagram showing where the radiator and condenser are located

Step 4: Remove the air intake. A large rubber hose connects from the right of the engine top (throttle body assembly) to the filter box. The rubber hose as a temperature sensor wire that needs to be removed first. Then pull of the hose with a twisting motion. The other side of the hose is connected to the filter box. There is a large hose clamp that can be removed to help free up mobility.

Diagram 2 - Engine Mount Removed

Step 5: Remove the air filter cover and take out the filter.

Step 6: There are two screws on the top of the air filter box (shown by the computer label  in In the photo below). Loosen these and open up the filter box. One of the control computers is hidden in this box. You will need to take out the computer (set is up on the engine – don’t damage the wires) and remove the plastic housing to get to the A/C lines.


Diagram 16 - Reinstall air box, pcm, hoses

Step 7: On the left side of the car, remove the battery. You will also need to loosen up the fuse box to help get the battery out of its little cubby.

Diagram 3 - Battery Removed


Step 8: Now unbolt the radiator assembly. There are two bolts (top right and left).

Step 9: Unbolt the fan assembly. There are three bolts (middle right and left, and top middle).

Diagram 4 - Radiator Assembly Bolts Removed

Step 10: Unclip the power wires that go to the fan.

Step 11: Unclip the transmission lines at the bottom of the fan assembly.

Step 12: Unclip the 3-4 wire harness holders that are attached to the fan assembly.

Step 13: Lift out the fan assembly.  You might need to loosen up and remove the right radiator hose to help make space.

Diagram 7 - Fan Assembly Removed

Step 14: Unbolt the A/C lies from the condenser. These are on the right side, in the middle. There are two. One is held together with a screw/bolt thing. The other has a plastic snap clip (you will likely need to break the plastic clip to get it off). The photo below is before the fan was removed.

Step 15: Unbolt the condenser lines mounting bracket from the radiator. Save this bracket! You will install it on the new condenser.

Diagram 6 - AC Hoses Connections

Step 16: Pull the assembly forward and lift out the condenser. That is the front exchanger. The back exchanger is the radiator and is attached. The photo below show the condenser removed. The condenser sits in 4 small clips that hold it in place. You need to either pry them open or just pull up and it will come out.

Diagram 8 - Pull back radiator - condenser removed

Step 17: Install the new condenser. Slide the new one into the front of the radiator. Make certain the new one sits into the 4 clips. Diagram 10 - Insert new condenser

Step 18: Replace the o-ring on the lines. I only replaced the one, you may need to replace both on the other line as well.

Diagram 9 - Remove old o-ring

Step 19: Install the fan assembly. Bolt into place. Clip in the transmission lines. Reconnect the power to the fans. Secure the wires into their clips.

Step 20: Install the condenser lines bracket.

Diagram 11 - Connect condenser tube bracket

Step 21: Connect the A/C lies. One uses the bolt, the other has the plastic clip.

Step 22: Move the assembly forward and re-bolt to the front of the car frame. Shown below where the screw clip is at.

Diagram 12 - Connect condenser tubes, wires, etc.


Step 23: Bolt the assembly to the frame on the left side too…

Diagram 13 - Bolt on fan and assembly to front of car


Step 24: Reinstall the battery.

Step 25: Reinstall the engine mounting brackets.

Diagram 19 - Reinstall battery


Step 25: Reinstall the air intake box, filter, and hose. Be careful not to damage the wires on the PCM Computer.

Diagram 16 - Reinstall air box, pcm, hoses

Step 26: Reinstall the diagonal support rods.

Step 27: Connect a vacuum pump to the low pressure line and pull the air out of the A/C system. It should hold a vacuum. (Note: the photo below doesn’t have the diagonal support rods installed yet.)

Diagram 19 - Pull vacuum on system


Step 28: Add freon. The sticker shown in the photo above (front of the car frame) indicates the amount of freon to add.

Diagram 20 - Add Freon


Step 29: (Optional) If you removed your radiator hose, refill the coolant.

Step 30: (Optional) If you removed the engine cover, replace it.




Fuel Tracking – May 2016

May Gasoline Use and Statistics:

Distance driven (miles)2,860
Fuel used (gallons)93.314
Efficiency (MPG)30.65 ± 1.1
Fuel cost ($)$211.81
Average fuel cost per gallon ($/gal)$2.27
Carbon dioxide released (LBS)*1,646
CO2 efficiency (LBS/mile)0.576

*Assumes 10% ethanol for 17.68 lbs-CO2/gallon.

Fuel Tracking – April 2016

April Gasoline Use and Statistics:

Distance driven (miles)2,782
Fuel used (gallons)94.996
Efficiency (MPG)27.9 ± 0.9
Fuel cost ($)$186.97
Average fuel cost per gallon ($/gal)$1.97
Carbon dioxide released (LBS)*1,679
CO2 efficiency (LBS/mile)0.603

*Assumes 10% ethanol for 17.68 lbs-CO2/gallon.

Fuel Tracking – December 2015

December Gasoline Use and Statistics:

Distance driven (miles)1,658
Fuel used (gallons)57.520
Efficiency (MPG)28.4 ± 0.5
Fuel cost ($)$103.50
Average fuel cost per gallon ($/gal)$1.80
Carbon dioxide released (LBS)*1,017
CO2 efficiency (LBS/mile)0.604

*Assumes 10% ethanol for 17.68 lbs-CO2/gallon.