Have a '90 Olds, 3.3 V6, 170K miles and lifter noise (this post is similar to the one below but it's not a Dodge) Have had this for some time. Have used both 5W and 10W's but no changes were noted. I've got in the habit of timing the noise before it goes away, roughly about 30 to 45 seconds ( I always let the car warm up, even when it's 150 ka-jillion degress in southwest Oklahoma in the summer time) Throughout the years, the time has remained constant, regardless of temperature or weight of oil. But once it's gone away after those seconds, it's gone until the next morning. You think switching to a synthetic oil would help? Have read all the pros/cons on switching to a synthetic oil on an engine that's this old and been this reliable. Doesn't burn oil at all and rpm's are still the same at a given speed as it was when new. Would maybe doing the Auto-RX help? I get the feeling like Dad always said "if it ain't broke, then dammit, don't fix it."