Dal do yaar jitna milta hay daal do sara.. 
Jokes apart, har 1300, 1500 and 1600 (not sure abt 1800) me 3.5 ltr oil dalta hay.... Get 4ltr can for the 1st time, u'l save 0.5ltr.... so when next time u go for oil change, purchase 3 ltr can+0.5 previously remaining and u're dont
Bottom line, 3 n a half ltr dalta hay.... 100%confirmed and guaranteed 