Answer by Japanese teacher
Petrol stations are called gasorin sutando (ガソリンスタンド) in Japanese. There are two types of petrol stations in Japan, full-service and self-service. Full-service petrol stations are those where attendants are on hand to fill up your tank as per your request. Self-service petrol stations are indicated by the セルフ serufu signs at the stations and you have to pump petrol by yourself.
If you go to a full-service petrol station, you can use the above expression. However, be sure to check with the rental car company what type of fuel you need for your car. Rental cars in Japan usually require regular (レギュラー regyuraa) petrol. However, it is good to know the other fuel types offered at petrol stations, which are high octane (ハイオク haioku) and diesel (軽油(けいゆ) keiyu). If your car requires regular petrol, you can also tell the attendant “レギュラー満(まん)タンでお願(ねが)いします。 Regyuraa mantan de onegaishimasu” (Please give me a full tank of regular petrol).