Fuel tank: 35 of 35 variants rated.
Renault 18 Combi TL tops the Renault 18 ranking by Fuel tank, at 57 L (15.1 gal US).
Across 35 ranked variants, Fuel tank spans from 53 L (14.0 gal US) to 57 L (15.1 gal US).
| # | Variant | Year | Body | Fuel | Fuel tank |
|---|---|---|---|---|---|
| 1 | Renault 18 Combi TL | 1984 | Wagon | Petrol | 57 L (15.1 gal US) |
| 2 | Renault 18 Combi GTL | 1984 | Wagon | Petrol | 57 L (15.1 gal US) |
| 3 | Renault 18 Combi GTX | 1984 | Wagon | Petrol | 57 L (15.1 gal US) |
| 4 | Renault 18 Combi TD | 1984 | Wagon | Diesel | 57 L (15.1 gal US) |
| 5 | Renault 18 Combi GTD | 1984 | Wagon | Diesel | 57 L (15.1 gal US) |
| 6 | Renault 18 Combi Automatic | 1983 | Wagon | Petrol | 57 L (15.1 gal US) |
| 7 | Renault 18 Combi GTS | 1982 | Wagon | Petrol | 57 L (15.1 gal US) |
| 8 | Renault 18 Combi TX | 1982 | Wagon | Petrol | 57 L (15.1 gal US) |
| 9 | Renault 18 Combi GTX | 1982 | Wagon | Petrol | 57 L (15.1 gal US) |
| 10 | Renault 18 Combi GTL | 1981 | Wagon | Petrol | 57 L (15.1 gal US) |
| 11 | Renault 18 Combi Automatic | 1981 | Wagon | Petrol | 57 L (15.1 gal US) |
| 12 | Renault 18 Combi TD | 1980 | Wagon | Diesel | 57 L (15.1 gal US) |
| 13 | Renault 18 Combi GTD | 1980 | Wagon | Diesel | 57 L (15.1 gal US) |
| 14 | Renault 18 Combi | 1978 | Wagon | Petrol | 57 L (15.1 gal US) |
| 15 | Renault 18 Combi TL | 1978 | Wagon | Petrol | 57 L (15.1 gal US) |
| 16 | Renault 18 Combi TS | 1978 | Wagon | Petrol | 57 L (15.1 gal US) |
| 17 | Renault 18 TL | 1984 | Sedan | Petrol | 53 L (14.0 gal US) |
| 18 | Renault 18 GTL | 1984 | Sedan | Petrol | 53 L (14.0 gal US) |
| 19 | Renault 18 Automatic | 1984 | Sedan | Petrol | 53 L (14.0 gal US) |
| 20 | Renault 18 GTX | 1984 | Sedan | Petrol | 53 L (14.0 gal US) |
| 21 | Renault 18 TD | 1984 | Sedan | Diesel | 53 L (14.0 gal US) |
| 22 | Renault 18 GTD | 1984 | Sedan | Diesel | 53 L (14.0 gal US) |
| 23 | Renault 18 Automatic | 1983 | Sedan | Petrol | 53 L (14.0 gal US) |
| 24 | Renault 18 TX | 1982 | Sedan | Petrol | 53 L (14.0 gal US) |
| 25 | Renault 18 GTX | 1982 | Sedan | Petrol | 53 L (14.0 gal US) |
| 26 | Renault 18 GTL | 1981 | Sedan | Petrol | 53 L (14.0 gal US) |
| 27 | Renault 18 TS | 1981 | Sedan | Petrol | 53 L (14.0 gal US) |
| 28 | Renault 18 GTS | 1981 | Sedan | Petrol | 53 L (14.0 gal US) |
| 29 | Renault 18 Turbo | 1980 | Sedan | Petrol | 53 L (14.0 gal US) |
| 30 | Renault 18 TD | 1980 | Sedan | Diesel | 53 L (14.0 gal US) |
| 31 | Renault 18 GTD | 1980 | Sedan | Diesel | 53 L (14.0 gal US) |
| 32 | Renault 18 | 1978 | Sedan | Petrol | 53 L (14.0 gal US) |
| 33 | Renault 18 TL | 1978 | Sedan | Petrol | 53 L (14.0 gal US) |
| 34 | Renault 18 GTL | 1978 | Sedan | Petrol | 53 L (14.0 gal US) |
| 35 | Renault 18 Automatic | 1978 | Sedan | Petrol | 53 L (14.0 gal US) |