Noisy hydraulic lifters

Every now and then I have a noisy hydraulic lifter then it goes then it comes back. I have tried using lucas oil additive and it has helped, is there a permanent way of fixing without redoing the lifters?

Jeff

No, has the engine had regular maintenence since new, not sludged up?

Regular maintenance and about sludge should you de-sludge your engine, i have heard negative remarks about that.

Jeff