Last post on May 31, 2013 at 10:33 AM
You are in the Cadillac CTS/CTS-V
What is this discussion about?
Cadillac CTS, Cadillac CTS-V, Fuel Efficiency (MPG), Sedan
#2 of 26 Octane/Check Coolant Updates
Feb 04, 2003 (11:21 pm)
First, the reprise of the Check Coolant message, after the dealer sealed the cooling system, seems to have been solved. When the message started reappearing, I noticed the overflow tank had been left open, with cap perched on the cowl. I replaced the cap, the dealer refilled the tank with DexCool, and the message hasn't reappeared in over a week.
Second, after the earlier discussion here on octane, I drove from Chicago to Toronto and back over the weekend, about 1200 miles. Used 93 octane going (which I had been using exclusively) and 87 returning. I always drive until the Low Fuel message, then invariably put in 16 gallons (the tank holds 17.5 per the manual), so by the second tank I think the residual 93 octane was negligible.
There were absolutely no differences in driving perceptions, highway, city or expressway, from one octane to the other. However, I did experience what I consider a very strange mileage phenomenon.
Keeping track of fuel consumption was really weird, because as soon as I crossed into Canada, I had to start using litres and kilometers (it's the law there, and you have to do it in French under risk of being arreted). Very confusing, especially when you multiply the metric hours by Canadian dollars and then convert everything to Celsius. Thank heavens the CTS has a computer to manage all these factors.
Anyway, driving east with 93 octane I got 24.0 mpg. Returning with 87 octane I got.....are you ready?.....26.4!!!! Both segments were essentially identical, highway speeds about 80 mph, negligible wind, comparable weather and the same terrain, and both cities are close to 600 feet above sea level, so it wasn't uphill one way and down the other. Temperature going hovered about 32F and returning was about 38F. I can't explain the difference, particularly the better mileage on lower octane fuel, unless the car just happened to "loosen up and break in" while on the trip (I have about 8K miles now).
In any event, I am going to use 87 octane from now on, unless something happens to change my mind.
#3 of 26 mcgreenx -
Feb 05, 2003 (6:11 am)
Do you know if Canada requires a mix of ethanol (or MTBE) in their gasoline? Our gasoline supply currently contains up to 10% of those additives. I experienced a reduction of about 1 to 2 miles per gallon when the government mandated a "clean air" gasoline mix in the early '90's. Your results may be due to that difference.
Our gas mileage is always better on a return trip from central or southern Illinois, when we go to visit my wife's relatives. I forget how many gasoline blends the government mandates, but the largest metropolitan areas get gasoline with the least amount of "energy" due to gasoline blend. Therefore they get less miles/kilometers per gallon/liter .
I think clean air is important, especially for kids, so I don't mind getting a few less mpg.
Anyway, your experiment has given me a reason to try 87 or 89 octane with our CTS, just to see if it makes a difference.
Jun 30, 2003 (11:15 am)
just got back from the southwest. drove 5000 miles and loved every minute of it. the cts averaged 27.6 mpg for the trip. did a lot of driving around 85 mph. only saw 7 other cts's and one that made me cry it had a vinyl roof. longest i drove in one day was 810 miles and i wanted to keep going. the car is very comfortable and handles great. only complaint it that the front of the hood and windshield chips real easy.
Jul 27, 2003 (5:49 pm)
I usually have an average mpg between 23.5 and 24 with my 03 5spd manual
Jul 29, 2003 (7:08 pm)
I usually get about 20.5 mpg in the city. Highway mixed driving I get about 26 mpg. I use 93 octane, sometime 91. The worst mileage I got was with 89 octane, 18 mpg in the city.
I probably could get better mileage if I didn't 'get on it' so often.
#7 of 26 CTS--87 octane
May 05, 2003 (8:02 am)
rsteph, my CTS turned 18k miles,including a 5K mile RT between Phoenix & Detroit. I have used 87 octane exclusively without any engine issues, knock, ping or preformance. The computer indcates 23+ avg. mpg. While I don't drive "at the limits" neither am I real conservative. I have NEVER been embarrassed by this cars performance,
on the Interstate or in town. I have used the xmission "Sport" mode on occasion and it does step things up a bit.
#8 of 26 Road Trip
Aug 07, 2003 (10:50 am)
My wife and I just completed a 925 mile trip from the Chicago area to Mackinaw City, Michigan and back.
The CTS handled superbly. It's definitely made for the road. We averaged 25.5 MPG, which wasn't bad considering we used the AC on the entire trip and ran into heavy rain on the trip up and on the trip back. We also had some major traffic jams back in the Chicago area.
Unfortunately, I had a problem with water under the drivers seat and on the rear floor. I ran a search on this discussion and located some earlier complaints along with the number of the service bulletin (TSB). The CTS is scheduled to go to the dealer on Monday.
Now that I've learned how to position my seat, I didn't have any problems with my right leg getting sore. Although neither one of us misses a lumbar support in our CTS, Cadillac should have provided one in the '03's, because when it comes to seating, "one size does not fit all".
As for brakes, the performance pads on our LuxSport are the best brakes I've ever had. The CTS stops quickly and in a straight line every time.
Dec 30, 2003 (8:50 am)
We just finished our second 650 mile trip to and from Southern Illinois this month. Since the steering wheel is adjustable and I tilt the seat back somewhat, there is no problem with placement of my hands.
I averaged 25.3 MPG on the trip, driving into a strong head wind on the leg going south. The CTS is great road car and is solid as a rock at highway speeds.
#10 of 26 CTS in the Snow
Feb 03, 2006 (12:11 pm)
I drove our 05 CTS in the snow last week. We had about 6 inches and the roads were icy and snowpacked. I put on Dunlop Sport M3 Winter tires this fall. The car has Stabilitrak. What fun! Between traction control and the Stabilitrak, there's alot going on to help. The car was impressive. Nothing like my Touareg, but not bad for RWD.
Comments on the previous post. A CTS is a good alternative to a BMW and no I-Drive; way cheaper than a 5-series and cheaper than most 3-series. We also try to buy GM if we are buying American, and the CTS is the hands-down best car they offer. Wouldn't take a Ford or Mopar on a bet. I doubt you'll see 25 mpg except on a nice level highway run below about 70 mph. Ours averages 19.8 mpg in almost 7000 mi of mostly suburban driving. That's the same as the 99 Olds Intrigue that it replaces, and way more fun. The car will go back to the dealer the first time for its first oil change, projected at about 10000 miles. In almost two years, my VW has visited the dealer no less than 15 times. I like both cars very much, though.