ya i got a 89' fleetwood with a 4.5 and it gets like 11 or 12 in city and 18 on highway. Thats pretty bad but im pushin on about 260k miles.

 

1989 Fleetwood

You keep that machine runni'n man. With that many miles and theyearof that car, that's still pretty good. The point we were trying to make is that our vehicles are rated at 28 mpg highway. I hope we can can get that kind of mileage.
My 2001 Deville N* did. ( 260,000 miles, AWESOME!)

Eddiek

 

My 2005 STS V-6 gets around 22.5 average and around 25 on the highway. I live in northern KY where their is nothing but hills and gas milage is never what is posted. I have swithed my OIL to Mobil one Full Synthetc 2W20 whichincreased my gas millage from the original gas milage of 19 average and 22 highway. Take care and good luck.

 

Doug

Thanks for the info. Do you think it's ok to go to a 2w 20 weight oil? Owners manual and dealership told me
Mobil 1 5W 30. Any other problems other than your Bose 5.1 and paint chipping? I had to have the steering shaft replaced at 300 miles and the steering gear at 500 miles. New hood latch also installed yesterday. Steering shaft rattled like my 01 DeVille Steering Shaft.Steering gear made a banging sound when turning the steering to the left. Service dept. couldn't believe my bad luck.They always give me great service and fix my problems promptly.



Eddiek

 

You know I got terrible mileage with my 92 Bonneville 3.8 V6. Sometimes I think an N* V8 in a heavy car like a Cadillac will do better than a 6 just because in theory it has more power and torque and you are not leaning on it as much to get it going and keep up with traffic. No science here just my impressions from driving mostly V8's anda few V6's for 33 years.

 

Katzman's Caddy,

That thought had crossed my mind too. However, I have had several large GM cars with the 3800 engine including a 99 Park Avenue that gave me 28 mpg on the highway. My 02 Bonneville SLE did good too. Being that the 3.6 vvt is whole different design, maybe the gas milage is going to be a litlle less. I can usually get the hwy milage that shows on the sticker in the past. City driving has always been more of a challenge. Most of my driving is city and the 3.6 is doing better than my 01 N*. I guess I shouldn't complain. You are correct that N* sure doesn't have to work very hard.


Eddiek

 

eddiek, katzmans.....agree with you guys.....the n* not having to work as hard........though have been in Parks, and LeSabre that have got 30+ hgh......... same engine in a Bonniville and doesn't get but high 20's...... i think the Buicks are geared different, something with the tranny...... you Techs would know, thats imo.
rickyd