Report "Loud lifters Change oil on 99 Montana. After 250 mile trip, I stopped and when I started it back up, I heard a loud lifter noise that got worse as I accelerated. I checked the oil and it seemed weird (kinda like syrup) (not a head gasket issue) I changed the oil and used valve medic and it quieted down about 85% but still have a noise when in idle and during initial acceleration. Seems to quiet down at highway speeds"