Drew,
I'm not sure about the "clackity clack" aspect, but I recommend using Valvoline MaxLife in the car at your next oil change. * I used this in mine for the first time around 6000 miles ago (91, 200QT, 149,000 miles now). I noticed an immediate improvement in power, the engine runs cooler (based on oil temp gauge, the engine temp is getting fixed tomorrow along with quite a few other things), and I went from 24 mpg to 25 (not huge, but, it is an improvement). Also, it doesn't use a drop of oil after 3000 miles (as a slight disclaimer to this, I never bothered to check the oil before I started my new job {see below} so I don't know if this is new with this oil, or if it's always been that way). With the first oil change with MaxLife, I also did a Valvoline engine treatment, this may help with the "clackity clack", it depends on what's causing it. The other high mileage oils and treatments may do the same, but I have no experience with them.
Hope it helps Bill
- Just to be completely upfront here, I am a manager of a Valvoline Instant Oil Change. Started around 4 months ago which is why I never bothered to check my oil, before then I came from a completely different line of work. I know this can be considered a conflict of interest, or self promotion, or whatever, but except for those of you that live in the southern New Hampshire area and don't do your own oil changes, it really doesn't benefit me so please keep the flames to a minimum :)