1985 Cadillac Fleetwood/DeVille (FWD) MPG & Specs — Real-World vs EPA, All Trims
Fuel grade varies by trim — see the breakdown below.
Is the 1985 Cadillac Fleetwood/DeVille (FWD) good on gas?
At up to 23 MPG combined, the 1985 Cadillac Fleetwood/DeVille (FWD) is better than average for a Large Cars — that class averages about 20.3 MPG across 2,605 EPA-tested versions, so it's a good pick on fuel for its size.
Real-world MPG vs the EPA number
The EPA figures above come from a standardized dynamometer test, not the open road — real-world MPG typically runs a bit lower depending on your driving, climate and terrain. That's true of every car on this site, old or new.
This 1985 model was originally EPA-tested under the pre-2008 2-cycle method, which didn't account for highway speeds over 60 mph, air-conditioner use, or cold starts. When EPA overhauled the test for model year 2008, city ratings fell by about 12% and highway by about 8% on average industry-wide — and EPA retroactively adjusted every 1984-2007 rating to the stricter standard so old and new cars could be compared fairly. The MPG above is already on that modern scale — the window sticker on this car when it was new likely showed a higher, pre-2008-method number.
At today's AAA national average price — $4.78/gal for diesel gas as of 2026-07-05 — the most efficient trim runs about $3,117/year (roughly $260/month, about $20.78 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 652 gallons a year. We don't estimate a cost-per-fill since exact tank size isn't in the public EPA dataset, but the per-100-mile figure scales to any tank. Current national average gas prices →
1985 Cadillac Fleetwood/DeVille (FWD) trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 4.1L 8-cyl, Automatic 4-spd, FWD | REGULAR | 18 | $3,167 |
| 4.1L 8-cyl, Automatic 4-spd, FWD | REGULAR | 18 | $3,167 |
| 4.3L 6-cyl, Automatic 4-spd, FWD | DIESEL | 23 | $3,117 |
| 4.3L 6-cyl, Automatic 4-spd, FWD | DIESEL | 23 | $3,117 |
1985 Cadillac Fleetwood/DeVille (FWD) specs
What the EPA test-car listings record for this model year — every combination sold is a row in the trims table above.
| Engine options | 4.1L 8-cyl · 4.3L 6-cyl |
| Transmission | Automatic 4-spd |
| Drive type | FWD |
| EPA body class | Large Cars |
| Fuel | Varies by trim |
Other years of the Cadillac Fleetwood/DeVille (FWD)
Similar cars (Large Cars)
Cars that take premium · Cheapest cars to fuel · Where fuel grade depends on the trim · Fuel guides
4 trim(s) · EPA FuelEconomy.gov data retrieved 2026-07-24 · fuel prices AAA national average as of 2026-07-05.