A grandfather clock will run approx. 3-5 years between oilings; 5-10 years between overhaul. A clock is a machine that needs lubrication and bushings (bearings) wear out over time. If your clock has not been serviced in the last 5 years then you need to call a professional in and he will determine how much wear there is and if it needs only lubrication or a complete overhaul.
Stevens Clocks, September 2009