Sorry Deo - mohammad is correct. 3/4 in this case means 75%. In the U.S., filters are (generally) sold with a small sticker on the outside. If one picks up an oil filter for the first time and tries to decipher the sticker, it may be nearly impossible to understand what it's trying to say.
Originally Posted by Deobulakenyo
But anywho, one of the sticker's instructions is to tighten the filter only 75% of 1 full turn tighter, AFTER the gasket is felt to touch. That gasket touch is very important. So, spin on the filter by hand. When you think you feel the gasket touch, go back and forth (tighter, looser) until you're sure it is the gasket starting to touch. Once you are sure, turn it 75% (less than) of another full turn, and leave it there. Gasket material makers specify a range of compression to their gasket material to a) get the job of sealing done, and b) not to damage or deform the gasket material. Evidently 75% of a full turn compresses the gasket into the specified compression zone.
I've never had a leak doing it this way. On this previous oil change, I'm not sure my big monkey arms were able to get a full 3/4 turn on the filter, but it should have been close. But I didn't have my tools. It must have been good enough. I always crank up the engine and watch for a leak, and it didn't leak this time either.
View my fuel log 2020 Mirage ES 1.2 manual: 42.6 mpg (US) ... 18.1 km/L ... 5.5 L/100 km ... 51.2 mpg (Imp)