I excited to be the new owner of a 1988 Mitsubishi Van. They are quite rare here in the States (imported from only 1988-91). Mine is an automatic, has a 2.4 gas engine, and boasts angular/boxy iconic 80s styling

I am preparing to do my first oil change. Vehicle has about 145,000 miles. Maintenance history is completely unknown. It does puff some smoke at start-up, which someone told me looks like a little burning oil.
Which weight of oil would you recommend? I am also thinking about adding a can of Liqui-Moly motor oil saver.
Thanks