The BMW 635CSi does 16 mpg combined (14 city, 21 highway), which works out to about $2,400 a year in fuel at $3.20 a gallon and 12,000 miles. Against other V6 cars it sits below the average of 19.9 mpg.
Every BMW 635CSi engine, compared
The BMW 635CSi was rated in a single specification, so its gas mileage does not vary by version — only by model year. Yearly cost assumes 12,000 miles at $3.20 a gallon.
| Engine | Combined | City / Highway | Years | Fuel per year |
|---|---|---|---|---|
| 3.4L 6-cyl | 14 / 21 | 1989–1989 | $2,400 |
What that actually costs
The BMW 635CSi burns a gallon every 16 miles, so 12,000 miles takes about 750 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.200 |
| Fuel per year | $2,400 |
| Fuel over five years | $12,000 |
| Against other V6 cars | +$470 a year |
| EPA's own estimate | $3,900 a year |
City or highway — who is this car for
The BMW 635CSi gives up 7 mpg the moment you leave the motorway — 21 out there against 14 in town, a 50% drop worth $914 a year. A wide gap punishes stop-and-start traffic; a narrow one means the car doesn't care where you drive it.
| Measure | Value | Reading |
|---|---|---|
| City | 14 mpg | $2,743 a year if you only drive in town |
| Highway | 21 mpg | $1,829 a year if you mostly commute |
| Gap | +7 mpg (50%) | Wide — this car dislikes traffic |
How the 635CSi changed over the years
Combined figure across the 1 model year the 635CSi was rated in, all of them at 16 mpg.
| Model year | Combined | City / Highway | Engines offered | Fuel per year |
|---|---|---|---|---|
| 1989 | 14 / 21 | 1 | $2,400 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 1 EPA ratings of the BMW 635CSi — 1 engine across 1989–1989. The mileage is EPA's laboratory figure, unchanged; the yearly bill is ours, at 12,000 miles and $3.20 a gallon, against EPA's own estimate of $3,900. Full method.
Frequently asked questions
What mpg does the BMW 635CSi get?
16 mpg combined on average — 14 in the city and 21 on the highway, per EPA ratings across 1989–1989.
How much does a BMW 635CSi cost in fuel per year?
About $2,400 at 12,000 miles and $3.20 a gallon — roughly $12,000 over five years, or 0.200 dollars a mile.
Which 635CSi engine is the most economical?
The 3.4L 6-cyl at 16 mpg.
Is the 635CSi good on fuel compared with similar cars?
Against other V6 cars it sits below the average of 19.9 mpg, computed across 4940 ratings.
Are these real-world 635CSi figures?
No — they are EPA laboratory ratings, the same ones printed on the window sticker, and EPA's own annual fuel estimate for the BMW 635CSi is $3,900 against the $2,400 we compute at 12,000 miles. Expect a little worse in practice: the spread between the city and highway figures is smaller than the spread between two drivers of the same one.
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