1998 Buick Riviera Gas Tank Size & Fuel Capacity
Fuel tank capacity
18.5gal · 70 L
The 1998 Buick Riviera has a fuel tank capacity of 18.5 gallons (70 liters).
A full tank is good for roughly 463 highway miles or 296 miles around town, going by the EPA ratings.
18.5 gal · Smaller than 52% of 1998 models we list.
- By trim
- Gas cap & parts
- Fuel essentials
- Miles per tank
- Fill-up cost
- Other years
- Compared
- Pump & gauge parts
- FAQ
1998 Buick Riviera fuel tank capacity by trim
MPG and range are city / highway.
| Trim | Engine | Drive | Tank | MPG city / hwy | Range city / hwy | |
|---|---|---|---|---|---|---|
| Supercharged 2dr Coupe 3.8L 6cyl 4A · FWD MPG 16 / 25Range 296 / 463 mi | 3.8L 6cyl 4A | FWD | 18.5 gal70 L | 16 / 25 | 296 / 463 mi | |
| No trim matches all of these filters. | ||||||
Tank figures are the manufacturer's rated capacity, sorted smallest tank first. Range is tank size times EPA city or highway MPG.
How far a 1998 Buick Riviera goes on a tank
Gallons left and the distance they cover at each mark on the fuel gauge, at EPA city and highway mileage. At the combined rating of 19 MPG, a full 18.5-gallon tank covers about 352 miles.
| Gauge | Gallons | Highway miles | City miles |
|---|---|---|---|
| Full | 18.5 | 463 | 296 |
| 3/4 | 13.9 | 347 | 222 |
| 1/2 | 9.3 | 231 | 148 |
| 1/4 | 4.6 | 116 | 74 |
| 1/8 | 2.3 | 58 | 37 |
Over 15,000 miles a year (the EPA's yearly estimate) this configuration uses about 789 gallons, roughly 43 full tanks.
Fuel gauges aren't perfectly linear and the low-fuel light comes on with a few gallons still in the tank, so plan your stop before the last eighth.
- EPA combined
- 19 MPG
- Tailpipe CO2
- 468 g/mi
- Source
- EPA ratings
What it costs to fill up a 1998 Buick Riviera
$78.99 to fill the 18.5-gallon tank from empty with regular, at this week's US average of $4.27 a gallon.
| Tank | Fuel | US avg / gal | From empty | From 1/4 tank |
|---|---|---|---|---|
| 18.5 gal | Regular | $4.27 | $78.99 | $59.25 |
By region, 18.5-gallon tank
| Region | Regular / gal | Fill from empty |
|---|---|---|
| East Coast | $4.02 | $74.37 |
| Midwest | $4.27 | $78.99 |
| Gulf CoastLowest | $3.70 | $68.45 |
| Rocky Mountain | $4.46 | $82.51 |
| West Coast | $5.42 | $100.27 |
| CaliforniaHighest | $5.89 | $108.96 |
Prices: U.S. Energy Information Administration retail averages for the week of October 26, 2026. This week's prices by state and city.
Your own price
- 18.5-gallon tank$78.99
- A year of driving (15,000 mi)$3,371
Starts at the US average for regular; type in what your station charges. For other tank sizes, use the fill-up calculator.
Riviera tank size in other years
The tank changed for 1998: 18.5 gal, down from 20.0 gal on the 1997 Riviera.
| Model year | Tank | Longest highway range |
|---|---|---|
| 1999 Riviera | 18.5 gal | 463 mi |
| 1998 Riviera | 18.5 gal | 463 mi |
| 1997 Riviera | 20.0 gal | 520 mi |
| 1996 Riviera | 20.0 gal | 540 mi |
| 1995 Riviera | 20.0 gal | 520 mi |
| 1993 Riviera | 18.8 gal | 470 mi |
| 1992 Riviera | 18.8 gal | 451 mi |
1998 Buick Riviera vs similar 1998 coupes
The Riviera has the largest tank of the two 1998 coupes compared here, 18.5 gallons against 16.6 for the Chevrolet Monte Carlo.
| 1998 model | Tank | Longest highway range |
|---|---|---|
| Buick Riviera | 18.5 gal | 463 mi |
| Chevrolet Monte Carlo | 16.6 gal | 448 mi |
Other 1998 coupes of a similar size, one model per brand.
1998 Buick Riviera fuel pump and gauge parts
These are the part numbers the makers list for the 1998 Buick Riviera. Check the fuel system recalls first: recall repairs are free.
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Frequently asked questions
What is the fuel tank capacity of the 1998 Buick Riviera?
The 1998 Buick Riviera holds 18.5 gallons (70 liters).
How many gallons and liters does the 1998 Buick Riviera gas tank hold?
The 1998 Buick Riviera tank holds 70 liters, or 18.5 gallons in US gallons.
How far can a 1998 Buick Riviera go on a full tank?
About 463 miles on the highway and 296 miles in town, going from full to empty at its EPA ratings. Expect less in practice, since nobody runs the tank dry.
How many miles can a 1998 Buick Riviera go on a quarter tank?
About 116 highway miles or 74 in town from the 18.5-gallon tank, which has roughly 4.6 gallons left at the quarter mark. Gauges aren't exact, so treat that as a guide.
What gas does the 1998 Buick Riviera take?
Regular unleaded. The label inside the fuel door confirms it for your car.
How much does it cost to fill up a 1998 Buick Riviera?
At the US average of $4.27 a gallon for regular (EIA, week of October 26, 2026), filling the 18.5-gallon tank from empty costs $78.99. It ranges from $68.45 in the Gulf Coast to $108.96 in California.
How much does a full tank of gas weigh in a 1998 Buick Riviera?
About 115 pounds for the 18.5-gallon tank. Gasoline weighs roughly 6.2 pounds a gallon.
Does the 1998 Buick Riviera have a bigger gas tank than the Chevrolet Monte Carlo?
Yes. The 1998 Buick Riviera holds up to 18.5 gallons; the 1998 Chevrolet Monte Carlo holds up to 16.6.
Sources
- Tank sizes: manufacturer-rated capacities from US-market specifications, checked against independent references. Updated October 2026.
- MPG and range: EPA ratings (fueleconomy.gov). Range is tank size times EPA MPG.
- Fuel prices: U.S. Energy Information Administration, week of October 26, 2026 (this week's prices).
Does your owner's manual say something different? Let us know and we'll fix it. More on how we check the numbers.