When we last wrote of our Long Term '08 Grand Cherokee test vehicle, we had only 4,000 miles on it, and the new car smell was still present. We talked about the power that the little V-6 musters up, and how the diesel is very quiet and could easily be used as a grocery getter, tow-rig, and commuter vehicle.
Now at just over 13,000 miles, about half of that towing another Jeep of some sort or another, two oil changes in, and having driven the entire West Coast from Mexicao to Canada, the new car smell and feel have both worn off.
Even with the new car smell gone, and the new vehicle rose colored glasses gone, we're still happy with the Grand. It is a great do-it-all vehicle, we still haven't had anything go wrong, and the only costs to date are fuel and regular maintenance.
Since the diesel isn't for sale here in California, we were concerned about taking it to our local dealership for maintenance, and we are more of the do-it-yourselfer anyway, so we decided to save some money and change the oil in our driveway. Due to how much towing and wheeling this Jeep sees, we are changing the oil every 6,250 miles.
We went with Amsoil 5W-40 European Car Formula and a Mann drop in filter. Not only is Amsoil dedicated to making high quality oil, it is made here in the USA with good availability. With 10 quarts to feed the crankcase, we got a 12-quart case.
What it really costs
You can figure out what your Jeep costs you to run, but for us, this Grand Cherokee is the cheapest Jeep in the fleet to drive. Keep in mind; this is in spite of record-setting high fuel prices over the past summer where it wasn't uncommon to see diesel at over $5 a gallon. Here is what we've got into operation costs so far:
| $2,913.13 | Cost of 601 Gallons of Diesel Fuel |
| $111.60 | Case of Oil (oil change number one) |
| $12.69 | Mann Oil Filter (oil change number one) |
| $111.60 | Case of Oil (oil change number two) |
| $12.69 | Mann Oil Filter (oil change number two) |
| $15.69 | Napa Air Filter (oil change number two) |
| $3,177.40 | Total Parts and Fuel $0.24/mile (over 13,005 miles) |
Real World Mileage
We like to figure things out for ourselves, and mileage is no different. One of the reasons that this Jeep is the cheapest in the fleet to operate is because its mileage, even when towing another Jeep, rivals the other Jeeps we've got floating around. And the numbers below include a lot of Los Angeles area traffic, and a not-so-light right foot. The other thing to consider is that unlike your buddy who doesn't really keep mileage or fuel logs, we do; and unlike your buddy, we really don't have anything to gain from embellishing our mileage. The only way any of our logs are useful is if we are dead on with our numbers. So, if you are at home trying to figure out if one of these is for you based on fuel economy, here are some real world numbers to consider.
Average Combined (towing, city driving, sitting in traffic, highway driving, wheeling) Fuel Economy: | 22.4 mpg (over oil change number one interval) | 22.2 mpg (over oil change number two interval) |
Average Highway Economy (no traffic at 72 mph): | 22.7 mpg |
Average Trailer Towing Economy (over about 6,000 miles of towing a dual axle car trailer with various Jeeps on it both around town, on the highway, and in traffic): | 16.7 mpg |
Worst Fuel Economy (from 5 hours in traffic towing a Comanche on a trailer): | 15.6 mpg |
Best Fuel Economy (on highway at 72 mph for a 400 mile trip into Arizona) | 24.7 mpg (we got 467 miles out of one tank of diesel) |
 The 3.0L V-6 engine requires...  The 3.0L V-6 engine requires a certain synthetic oil which meets Mercedes Benz MB 229.51 or Chrysler MS11106 specifications. It takes ten quarts of oil and a replaceable drop in oil filter. We went with Amsoil's European car formula oil and a Mann filter for a total cost of $124.29 in our driveway. |  Tongue weight is important...  Tongue weight is important when towing. There needs to be enough tongue weight to make the trailer and tow rig behave as one unit when going down the highway, but not so much as to pick the front tires of the tow rig up off the ground and cause handling. With a soft and supple coil sprung rear suspension, we expected not to be able to get enough tongue weight before steering was affected, and while a weight distributing hitch would make this tow much better, so far we are doing fine. |  We were having problems with...  We were having problems with the My Gig navigation system. It would "forget" where home was, get stuck in an endless loop of "Calculating Route", and occasionally would have no sound at all. The only fix to any of those problems was to shut the Jeep off and let it sit for 10-30 minutes. We were researching swapping the unit out when we found an updated ROM, available from our dealership that brought us up to version 9.807 and cured 97 percent of our problems. |
 In hotter weather, while towing...  In hotter weather, while towing and going uphill on the freeway, we noticed our temperature gauge creeping up. We anxiously kept an eye on it, but it never got past here, and it never boiled over. We've heard that this diesel engine doesn't deal well with overheating and one trip to the red could possibly lead to internal engine problems. So far, so good. |  The front and rear disc brakes...  The front and rear disc brakes on the Grand are good, but not up to the task of repeatedly stopping a 5,500-pound vehicle with a 7,400-pound trailer behind it (the rated tow capacity). So, we mounted this Tekanosha P3 electronic trailer brake controller in this Jeep-included cubbyhole, wired it into existing wires that were part of the tow package, and now can safely tow and more importantly stop any trailer up to our rated capacity. |  |