petrol tank vs gas tank

petrol tank and gas tank both are nouns.

Word	Noun	Adjective	Verb	Adverb
petrol tank	Yes	No	No	No
gas tank	Yes	No	No	No

As nouns, petrol tank and gas tank are synonyms defined as:

petrol tank and gas tank: a tank for holding gasoline to supply a vehicle

Other synonyms of petrol tank include gasoline tank.

petrol tank (noun)	gas tank (noun)
a tank for holding gasoline to supply a vehicle	a tank for holding gasoline to supply a vehicle