The M116 is as hardy as they come. Probably due for a timing chain and rails if it hasn't had the job done recently. 1987 might have been an iffy year for valve seals. Coming to the end of the typical original transmission life as well. A well cared for car might have had all these items addressed recently in which case it should be good for another 200K miles. Definitely worth the investment in these major service items if they're due.